How To Do a Repair Install of XP
Make sure the BIOS is set to boot from the CD (put
the CD above the HD in the boot order)
Insert the XP CD and boot to it
When you see " To setup Windows XP now, press ENTER", go
ahead and press ENTER
You will now see an option to repair Windows by pressing "R".
Do not select this option - it will only take you to the Recovery
Console which is not what we want to do. Instead, choose to continue
the installation
When you see the license agreement, press F8 to agree
On the next screen make sure your current XP installation is selected
and then press "R" to repair XP
At this point XP will begin to install on top of itself, replacing
damaged, missing or altered system files. Follow the instructions
on the remaining screens to complete the Repair Install. It will look
very much like a normal (new) OS installation. If all goes well your
repaired XP installation will remain iintact, keeping your personalized
settings and installed programs as they originally were. Remember,
choose the second repair option, not the first.