|Looking further into the error message it looks like the hard disk has become corrupted..|
There are a few recommendations - if you have a windows XP CD (probably came with your computer, likely labeled as repair disk) you can boot that and perform a check-disk.
1)Boot Computer with CD in
2)When CD has booted, R
3)Leave administrator password as black, or type in if you know
4)type in "CHKDSK /R" (without quotes)
5)reboot and (hopefully) it will load successfully!
I am running this from personal experience,but in the long run I would recommend backing up your personal files and replacing the drive, as it is likely that more problems will be experienced as the drive ages
Hope that this helps!