I'm cobbling together a machine from parts my son gave me, all new , unused. Only had to buy a case. He's gone for a mo. so can't ask him. Here's the prob: the only part that's not new and unused is the HD. I took it out of one of my other machines. It's a maxtor, maybe 3 mos old with XP pro on it. The machine it was in has a P3 500 chip in it on an old intel (dell) motherboard, (and bios) The new MB is an 800mgz fsb with a P4 2.6 chip. When I turn it on all fans work, the monitor works, it runs thru it's bios thing. It recognizes the HD,CDRW, AGP card, proper memory amount. The screen says "we apologize, windows did not start successfully, a recent hardware or software change may have caused this" What do you guys think?