CIV IV locking up

[cesareDH]

I've been playing the game since the first day it was released with only one small persistant problem, the cursor stutters bad. I've lived with that and everything else seemed to work fine until last week. After I installed a new slave drive, the game started locking up for no aparent reason. I've completely uninstalled it and reinstalled it + the v1.5 patch. The game's still locking up without any warning.
Please help.
Thanx
WinXP Pro
NVidia 6600 video
1024MB RAM
160G "C"
80G "F" (slave)