Did you remember to turn off one of the cores via MSCONFIG?
That is usually the culprit.
As I've learned recently, most or all games will freeze in dual core mode. Freezing can also be because both the Microft dual core drivers (KB896256) are loaded as well as the AMD.
Actually, better off [except for that recent disappearance] to have the BOOT.INI with two separate lines, one with dual core and one with the " /numproc=1" set.
Using MSCONFIG ain't the best way as you have to go back and forward and remembering to reboot after changes.
My setup (NOTE: Yours may differ because of the number and types of dics and setup):
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /noexecute=optin /fastdetect /usepmtimer
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Pro Gaming" /noexecute=optin /fastdetect /usepmtimer /numproc=1