OK, I set the affinity to only one CPU and it fixed it for a few seonds after I switched into the game and then it went slow again. I opened the task manager again and it was still set to 1 cpu. I switched which CPU it was using and it was still slow.
Windows XP Home SP2
Intel Core2 Duo E6300
ASUS P5N32-SLI Deluxe
3 x Kingston 1GB PC-2-5300 DDR2 SDRAM
2 x Seagate 300 GB Barracuda 7200.9 SATA II (Striped RAID)
eVGA e-GeForce 7900 GS 256MB PCI-E (NVIDIA GeForce 7900 GS)
That should be everything relavant