I built a rig for a friend last year and he told me this week that the system had stopped booting. So I went to have a look and found fault which I find hard to explain. When I switch the system on, it gets through the POST screens and then halts with the "non stystem disk retry/fail/abort?" (or whatever it says). I tried all sorts from re-setting the bios, running chkdsk, fixmbr, fix boot to no avail. Then on one particular re-start with the Windows XP (SP2) CD in the drive I let it start-up without going into the CD and Windows booted (and operated fine). However, when I tried to re-start again without the Windows CD in the drive, the boot failed again. Basically the computer is only booting into Windows if the Windows CD is in the CD drive. It's got me puzzled, any ideas?