Thanks in advance. I'm putting together a computer for a friend using parts saved from various systems I've changed over the last year. Leadtek Nforce mb AthlonXP 2000+ 512 M DDR 2700 ATI 9200 video onboard sound, lan Asus 40x CD-rom WD 60GB EIDE hd WinXP home SP2 Everything installed well, up and running smoothly. This weekend, I started getting an error message on start-up about invalid boot disk, insert a valid boot disk and press any key to proceed. I checked all the cables, plugs, etc. I booted to the Windows CD, went to the repair console, and repaired the MBR. The computer booted just fine. Until the next time I turned it off and tried to reboot (both warm and cold boots). Exactly the same error. So I did another FIXMBR, and then did a full chkdks. No errors reported. THe computer booted fine...until the next time I turned it off. Unfortunately, leaving the computer on 24/7 is not an option. I have installed no software other than winxp, sp2, and MS Office. The installation was a fresh install on a newly formatted (although used) drive. Do I just need to replace the drive, or is there something I'm missing?