Setting CPU affinity in XP

Hello,

I had tried to set affinity for RA1 on my XP. (yes I know, an old game, but still a fav)

Anyway, I set it to 1 cpu thread but now I think I would need to use both core (8600). But when I go into Task Manager - It is always now set to 1 cpu.

If I change this to 2 cpu, going back into the game - it freezes on me.. I cannot set this anymore back to normal dual core mode..

Anyone had this kind of problem before for anything?

Thanks

~Hen