I have an older DFI AK75-EC Rev E+ with a 900Mhz thunderbird and it runs fine. Today I picked up an Athlon XP 1800+. I've flashed my BIOS and everything else that I can think of. But the damned thing wont boot. But if I put the 900 T-Bird in, it boots right back up. Does anyone out there know what might be the problem???