yes it is defiantly now your drivers fault. My suspicion of ram as to why it crashed also involves new models being added to the map and new animations being played. The game is still directx 9c, so maybe try updating all of your directx including a directx9c? if thats possible in windows 7?
I have a suggestion for you to try:
Try running in XP compatibility mode on Dof.exe and DoFUpdater.exe in the main directory.
otherwise, you will just have to jump around gpu drivers until one works properly.
Also a word of advice, when it comes to hardware, stay 8 months behind, just like dof in that developers need time to work out the kinks.
I'm gona buy a 480gtx in a month or 2, I got a geforce 9600gt atm HA