|Your hard drive may be in the process of failing. If so, there may or may not be essential data necessary to restore the original software in the hidden second partition on the hard drive that has damaged data, or even if it doesn't have that, the Recovery procedure may fail because of "visible" bad sectors being on the hard drive. |
Check your hard drive with the manufacturer's diagnostics.
See the latter part of response 1 in this:
(thanks to Dan Penny for this link:)
Hard Drive Diagnostics Tools and Utilities
If you don't have a floppy drive, you can get a CD image diagnostic utility from most hard drive manufacturer's web sites, but obviously you would need to make a burned CD, preferably a CD-R for best compatibility, on another computer if you need to.
If you have a Toshiba hard drive, Toshiba has no hard drive diagnostics. The Seagate SeaTools program will test any brand of hard drive (use the long test) , but can only attempt to get rid of (fewer than 100) bad sectors on Seagate and Maxtor hard drives.
If the hard drive itself tests okay, any data problems found can be fixed, one way or another.