Well Sou, I am VERY happy to inform you, that the Realtek device RTL-8139 IS SUPPORTED in the kernel so, providing that your kernel is compiled with the realtek module r8139 built in or as a module, you will have good support.

Do you have internet using Linux right now?? Or is this unstable connection happening with Windows?

Here's another command to try, when in LINUX:

sudo lsmod | grep 8139

and if you get a result back, then that means the support is built as a module, and is installed.

If not, then try

sudo modprobe r8139
or
sudo modprobe 8139too
or
sudo modprobe 8139cp


If no result comes, it is a good sign that the module has been installed, and with little or no more configuration, you should have internet.
If there's an error, then check in the folder /lib/modules/<your-kernel-name>/ and check in the folders in there, probably a folder called 'net', and see if there is a thing in there called "something-8139" or "8139-something". If you see it, note the exact name, and try the modprobe command again like above, using that name, but WITHOUT the .ko extension.

I recommend for the time being, you go into your computers BIOS, and if possible, DISABLE the Attansic L2 ethernet device. Windows will use your new card just as well as it will use the other one, so for easier configuration and less confusion in Linux, disabling the Attansic onboard device is the thing to do.
Please try this, and let us know how this goes. You are very close now.

Dear GrapeFruiTgirl,

Thanks for the prompt advice. But, as of now I am in a hell! Let me tell you the incident...
1. I thought I should install Mandriva 2007 along with the UBUNTU & XP. I installed it.
2. When I rebooted the machine, an error came up and said " grub bootloader error" or something like that. Nothing was loading.
3. So I called one of my friend and asked him for a suggestion. He told to insert the Windows XP CD and in the repair console type: fixmbr
4. After I did it, and the machine rebooted, there was no option to load the three OSes, and the machine straightly booted into XP!!!!
5. Several times I have tried, but with the same result!!!

(Now I am writing this post from Windows XP). Please help so that I can get back the option screen during booting.... (and then only I shall be able to boot into UBUNTU/MANDRIVA).

I have 160GB Sata HDD.
10GB for Mandriva
8.5GB for UBUNTU
1.5GB for Swap Area
Rest GBs for XP.

Hello friends, I have re-installed the UBUNTU again..!!

And here goes the output:

sou1234321@ubuntu:~$ sudo lsmod |grep 8139

8139cp 25088 0
8139too 27648 0
mii 6528 2 8139cp,8139too

And as per your advice, I have gone through this folder:
/lib/modules/2.6.20-15-generic/kernel/drivers/net

and found a file called "8139too.ko", then in the terminal...

sou1234321@ubuntu:~$ sudo modprobe 8139too
sou1234321@ubuntu:~$

Now, what to do friends?

As GrapefruiTgirl said above, that you get no output after a modprobe is usually a good thing. Have a look here for more instructions on setting up your connection.

Well Sou, according to the results of the LSMOD command you did, your ethernet card is installed, identified, and the drivers are installed too. So as far as installing it, you're done

Now, you need to probably do some very minor configuring of whatever files are used on Ubuntu to tell the system HOW to use the internet.
In your START menu, you should somewhere find a menu item called 'Internet devices' or 'Network Configuration' or 'internet connections' or something along these lines. Since you are using Ubuntu, I think you will be able to do whatever needs to be done by using that GUI tool.
Since I don't use Ubuntu with any regularity, I suggest you inquire of another Ubuntu user (or wait until one offers help here) as to what 'Network Settings Tool' you should be using to set up your internet connection, and how to do it. I suspect the tool will be quite self explanatory, however if anything is unclear with it, or if you cannot locate such a tool on your system, please let us know, and I'm sure that another Ubuntu person will point you in the right direction.

NOTE - Since LSMOD told us that the 8139too module was ALREADY installed, you did not need to do the 'modprobe' command. It didn't hurt, but it appears that Ubuntu is automatically doing it for you.

So, find that GUI for your Internet Connection Settings .

EDIT - I see Nylex has posted a link for you above; I haven't checked it out, but you should; it might be just what you need

Dear Nylex,

Thanks a lot for prividing the link. But, I already have a printed copy of that.

However, let me clear out the problems. It's not like that I couldn't access the internet at all, but the fact is that the connection is not remaining stable, in spite of all these hardware change, tweakings, etc.

When I am trying to download the codecs for MP3, at first it's downloading like a storm, then after 4 minutes, there is no inbound traffic at all (as I can watch in the system monitor graph), hence the download of codecs are getting failed repeatedly.

I have tried re-installing UBUNTU for at least 7/8 times for the last 3/4 days!!! But no luck! As per your advice, I have changed the hardware, posted the output... but...

Perhaps my luck is worthless...

Can someone help me or do I have to give up trying Linux (due to my ignorance)?

You guys in this forum are extremely helpful. In fact, it's due to your endeavour, that I am able to connect internet at all. But still, I am getting a notion that the last door will probably remain closed for me ever...

Does the connection act like this (dropping out, etc..) in BOTH Linux and Windoze, or is it ONLY in Linux?

Let me suggest one thing first Sou: reinstalling the Operating System repeatedly is not going to accomplish anything. It's wasting your time, and if nothing else, probably setting you backwards as far as any tuning, changes, tweaks, etc, that you may be doing or will do.

Don't give up. You HAVE a connection; it might be an intermittent one, but it is better than NO connection, right?
Be patient, and don't be so hard on yourself. You're brand new to Linux, and you will learn from both your mistakes, AND by doing things such as this process of getting your internet working.

In the past, I have had my internet connection appear to be cutting out on me, however, let me explain what the problem was: My ISP (my internet provider) decided that I had been using too much bandwidth when I was downloading stuff, and so after a while, during my download, they would cut my bandwidth down so bad that my download would stop.
It took me quite a while to diagnose this issue, and to the very end the ISP officially denied it, but a tech person there was kind enough to explain that this was very likely what was happening.
We ultimately switched from that terrible psovider, to another one, and I have NEVER had that problem again, proving the theory IMO.
Now, here's an idea, which you may or may not have already tried: What are you using to download with?? If you are using your browser, I suggest NOT doing that, and instead use a Download Manager. This way, if a transfer stops or dies, you can almost always resume it. Just pause it, or stop and restart it a moment later, or whatever. Using a browser is not a good way anymore to download large files.

If this idea does not work for you, then we will need further information, or some sort of evidence or proof as to what exactly is happening to the connection, and when, EXACTLY how often if it is at regular intervals, before any further diagnosis can be made.
Hopefully someone else will have more ideas, or other options to try out. Meanwhile, consider what I have posted here, and provide any further info you can that may help us figure it out.

Thanks
Hang in there..

Sounds like his DHCP lease might expiring/renewing on a ridiculously short cycle. Something from his syslog might help narrow the scope of the problem...

Dear Well-wishers,

Thanks again for the advice. I am facing problem only in UBUNTU. My internet connection is working okay in XP (by God's grace).

The ISP that I am subscribed to is the only ISP in my locality. However, no such incident happened in the past to make me feel that the ISP is screwing me. In fact from XP, I have dowloaded several movies without any hassle. Basically, I have subscribed to the unlimited download plan (for which I am paying them good bucks...)

I didn't understand what you wanted to mean by "dropping out..."

And moreover, I am using synaptic package manager of Ubuntu to do the codec download. What is happening is something like this:

Suppose there are 75 files to be downloaded. For the first 4/5 minutes, it's downloading like a breeze (with the rate of download speed displayed under the progress bar) then suddenly the connection vanishes (and in the rate it displays "unknown rate").
Again it comes back after 4/5 minutes and then again vanishes... so on...

Generally, I keep open the System Explorer, where I can see from the real-time graph that the connection disappears...!

And well, what exact information I can supply you for detailed analysis? I am ready to submit (but u should at least guide me how to get the reports u want... )

Lastly, I am moved by the concern you people have for the Linux community members. Hats off to you people...

Hi Sou,

I am just going to observe for now, and probably learn something myself too. Since I don't use Ubuntu, and also don't use DHCP nor know where to look in an Ubuntu file system without guiding you all over the place looking for I-don't-know-what, I anticipate some of the others will have more accurate info to help diagnose this problem.

Remember: it WORKS we just have to make it BETTER now

Dear GrapefruiTgirl,

You have rightly said. It's true that none can claim that he/she knows all. In fact this gives me a consolation as a Linux Newbie...

However, though I should not ask like this but couldn't resist myself. Probably u are using multiple distro(s), but what I want to ask what are the distros u r using? May be if I can use one of those distros (obviously, if it can be used by someone as idiot as me... ), you can guide me accordingly.

Please forgive, if I have 'dared' to know something personal from you...

Nah, that's FAR from personal. After all, sharing Linux this-and-that is why we're here, yes?

Well, mainly what I use is in my sidebar on the left hand side
<----------- over there.. Slackware 11 with a LOAD of extras; Slax Live CD; and EasyS with a few extra tools.

They're all Slackware-based distros, but 98 % of the time I use my primary Slackware 11, which has a whack of stuff added to it and is my 'pride and joy' besides my pet snake.

I use the Slax Live CD for A) emergencies if my computer is totally $#$%@ed up, and B) if I want to boot something on another machine, like for example an old laptop we have around here, or C) if I were going to go to someone else's computer and load or do something, like web browsing, filesystem work, etc, I would use Slax.

I use EasyS in its nearly-stock configuration, for booting up and chrooting into my Slackware OS if need be, to fix things if they break, which they RARELY ever do unless I have manually broken something and I also use it if I do something stupid to my Slackware and I need to restore my system from one of the daily backups I have automatically happen every day. I just boot EasyS, mount my Slackware partition and one of the backup partitions, and copy everything over. Takes like 5 minutes, and Slackware is fixed

Slackware may not be the best choice for a new Linux user. In my very humble opinion, it was a great choice for me, (and is an extremely agile, capable, customizable, stable, and fast distro), as I have had the time and inclination, and interest, to spend a great deal of time fiddling, tuning, tweaking, and learning about it, and I am very happy that I chose Slackware without too much ado while trying out distros back when I switched to Linux. I love it. Chances are, you would love it too, but it would take a long time to get everything *just* the way you like it. There are virtually no GUI things for doing stuff, you must edit text config files to make things do what you want. This is great, but if you want an 'Automatic' distro out of the box, that does everything the way you like right away, Slackware is a big, powerful, wrong way to go. If you are willing to take the time to set Slackware up, one thing at a time, over several weeks/months, until it is perfect, then by all means, go for it! And there is totally LOADS of support and help here on LQ from a great Slackware community.

Thanks for the suggestion.

In fact, a few months before, I was gifted with a bootable CD of SLAX which came as a bonus pack with a computer magazine. But I can't remember the version. Anyway, but it was well decorated with GUI sort of things. Practically, that was a live CD I was using.

I don't know whether the name "SLAX" has something in common with "SLACKWARE", but let me confront that I really dare to do something in "command line" interface. It has been my prejudice that dealing with command-line stuffs obviously needs a considerable expertise.

At least, someone should be within your reach if things go wrong with all the data being vanished from even XP itself (after all it's an operating system) and the next day my boss kicking me out...

Frankly, I can't afford to lose the datas of XP.

Nevertheless, the image you have depicted regarding slackware has scared me. It has always been one of my nightmares to work without GUI..!! (as all of u have figured from my earlier post(s)).

But the concept of EasYs is appealing to me as it may save my life (literally) if back-ups are gone...

Does that says to keep myself away from slackware?

And well, what about the hardware recognition power of SLACKWARE?

Sou, try pclinuxos, it is easy for newbies like you and has good hardware recognition, the link is http://www.pclinuxos.com/

Dear dv502,

Thanks for the help/suggestion.

The fact which I am looking after right now, is not only an easy distro but also a distro which has quite an adequate number of members to help out in case I run into some incredible problems.

Some told Ubuntu is easy. Yes, I must admire that Ubuntu is easy, but perhaps most of the linux user, once they become experienced, jump on to some better distro.

Though I don't consider an experienced user at all, not even novice (but even below that), but still I think that it would be better to use a distro which has more experienced users to help the irritating people like me...

Don't take my words in wrong way. What's your opinion?