win2000 won’t boot past blue screen.

I just replaced a amd 1.13 w/ an xp 1800. The pc seemed to be working fine until I started getting kicked out of my first person shooter game. Now it has rebooted on its own and will not boot up past a blue screen that flickers for a split second and then it reboots all over again just to do the same thing over. I have tried a safe mode boot and the same thing happens blue screen and all. I want to think it is my mobo failing. Any help is appreciated.