should probably identify whether the problem occurs in normal M:TW and not the modded version - or in the modded version only.

The problem with NVidia drivers (for me) was ALWAYS the transistion to and from campaign mode - I could run quick battles and custome battles and historical battle ok - but when I tried a campaign - the loding of the campaign code was where it CTD - my fix was to roll back my Nvidia drivers - so the latest drivers are not always the best solution - good luck