After upgrading CPU, can't boot or reinstall WinXP

I have WinXP pro and when I upgraded my AMD 1800+ to a
2400+ WinXP would not boot past the loading windows
splash screen. Same when doing a fresh install of WinXP.
I know the AsusA7V333 mobo reconizes the CPU because I
have WinME and Linux running now. I think WinXP won't
load because of the hardware upgrade and I was wondering
if anyone knew how to fix or a work around for this?

Thanks in advance,
Kent