I don't know if this info may help some one, but my machine got itself in a right pickle. i tried to format it but could not, windows xp cd's seemed to be non bootable. i tried this and that. i also tried the 6 disks that enable you to get into the setup.
it came up with some error on the second disk.
i figured that i had some sort fo bad virus(boot sector ?) which ahd affected something vital, and was messing around with my system files.
i got my old windows 98 cd, inatlled windows 98, found out that there is some sort of problem running windows 98 on a processor above 2.1 GHZ. and then reinstalled windows xp.
problem solved, hope this helps some one , cause i was really fed up.