I had the same thing happen to one of my old computers (the motherboard in my case was crap anyway), and it turned out being a dead motherboard. I'm guessing putting in the new processor was too much for it and it killed it, which is why it won't accept the original. You mention the motherboard supporting up to an 1800+ Athlon XP, right? Putting in the 2000+Athlon XP probably killed the motherboard.ToM_E said: