I installed Linux Slackware 10.1, and the first time it booted nice, no problems i loged on as root installed the sound drivers, got into kde with startx, then i loged out, and when i tried to boot another time in linux i got something like:
"You have some filesystem with errors. Force check" or something and i waited to check... then it prints something like:
"Press control+d to restart or enter the password", if i enter the password i have no acces with user root. I installed it twice. Do you know why is this happening? I'm a noob... this is my first linux ever.
I will really apreciate if you answer.
Bye.

That means you have screwed-up your hard disk (don't be afraid, though, there is a way out.)

Enter the root password 'for maintenance' when asked.

Then use cfdisk to check your root partition.
See and for more info.

OOPS! I meant fsck (file system check) instead of cfdisk there. Sorry!

Ok i'm a total noob so i would greatly apreciate if you could tell me what to do...
I mean after i type those commands what other commands do i have to type?
Why did i screwed up my hard disk?
I really apreciate your answers.

When it asks for password, type it. Then type :

e2fsck -v -y /dev/hda1

replace /dev/hda1 with the name of your root partition.

After the command returns, type reboot, the next time everything should be OK. (NOTE: this works if you have ext2 or ext3 fs only)

Well, it is not so hard to screw up a hard disk.
A power failure, the accidental hit of the RESET button etc. can lead to a corrupted sector on the hdd.
I once got into the same mess while trying to install a initrd kernel image on my good 'ol Woody.

Thanks a lot. The 3rd time i installed slackware i chosed ext 3 and everything seems to be in working order. I will keep that in mind.. what you have written.
Many thanks.
Bye.

EXT3 is better, but it isn't fail-safe, just like any other FS. It's just able to correct itself by itself , and is easier to mantain.
EXT3 = Future!

While ext3 is better the same thing can happen with it. The solution is the same as above. Every 20 mounts (or so) the partition will be checked for errors (this number can be changed with tune2fs) and often something like this happens.

EXT3 gets scanned much faster than EXT2, as it has a journal.