I cannot boot Wind. XP in my PC; in console mode, using chkdsk /r, the message is "..irreversible errors", if I try to reinstall XP it asks to reformat the disk.
So I used Koppix to recover my personal data and I succeded.

Now, I'd like to know if I can do more, making me able to reestablish the previus conditions.

I tried Testdisk; the "analysis" menu that warned "bad ending head (CHS and LBA dont' match)" and then "proceed" obtaining "The current number of head per cylinder is 16 but the current value may be 255. " In my bios realy the number of heads is set to 16, but in any case, I tried to change it.
I used "geometry" to change the number of heads, but it seems to me that it did not write this info on HD.

I'm not sure if I'm am on the right way to fix the problem.
Can someone suggest me how to go head?