Have a few questions relating to the Ubuntu directory. I have a dual boot XP/Ubuntu system:

1. I noticed that there is a /windows dir. Surely this is a security compromise, ie. an infected file in Windows could easily be imported into Ubuntu. What is the point in having windows system files that could intefere with Ubuntu?

2. I noticed that GRUB is based in the /boot dir. What would happen if this was deleted by accident?

3. Would like to install Windows 7 in an external drive. Can this be done by booting from the BIOS to the external drive and completely by passing my XP/Ubuntu dual boot (as well as getting an ethernet conection) so I can install and test W7?

Many Thanks.

Congratulations. As I understand it dual-booting is hard enough. I am not sure why you are worried about Windows co-existing with Ubuntu.
As I understand it, a Windows virus is not unlikely going to affect your Linux (Ubuntu) system, given a lot of viruses are targeted at Windows OSs.

Can you see these files from the Windows system?

There may be some other issues covered in

https://help.ubuntu.com/community/WindowsDualBoot

"Imported" (as in copied to) yes, executed I doubt it. However, if you are interested, you might get some viruses working in wine if you try hard

It won't boot, since the kernel usually is there. It would be like deleting ntkrnl in windows. However this could be fixed by using a livecd.

If your BIOS supports it you can set it up to boot from USB. It should also be possible to set the boot order (just like you set it up to boot from cdrom or floppy). However, note that you could also add an entry in your already existing grub.conf/menu.lst to boot from your USB drive. That way you won't need any special setup in your BIOS, and you will be able to choose what to boot at boot time.

Thanks - I suppose there are a few options here relating to booting from USB. I'll probably take the safest route. After spending months fixing 3 computers enough is enough!

Re. cmnorton's response, it looks like all windows files are in /windows. For example, I went into windows/WINDOWS/system32 and the HDD started working (like how XP is (noisy) compared to this fantastic Ubuntu find...). I backspaced and didn't wait to see what would happen. I did though access some of my documents in the windows C:\ drive and save to open office.

What I'm surprised at though is that this available on Ubuntu. I suppose if the applications caused a problem they would not have been included in the Linux design.

One more question - if I use my yahoo mail account through Ubuntu, does this risk more viruses or should I just use it on my XP partition?

It depends on what do you mean. Yahoo shouldn't be a problem any more than any other mail account of a different provider.

If you receive a mail with something that can be run under linux attached, and you run that file then anything can happen. It's not different to this case where you download something from an unknown web page and you run it without even bothering to check what it is.

However, attachments that are executable under linux are very rare.

Some mail clients (if you use one instead of webmail) can integrate with AV software (for example, I know that kmail can work together with clamav).