1. Dowload/Install Driver sweeper but dont run it. Download those ati drivers.
2. Run setup of new drivers and then run the uninstall part. Will search your current install then auto-delete and say reboot.
3.Reboot and press f8 as it is booting for safe mode. (You could also press del to enter bios but no need atm). It might be a different key press, dpends on your mobo and bios. Your manual should say. Btw reading a mobo manual, however dull is a good idea.
http://www.google.co.uk/#hl=en&source=hp&q=Safe+mode&meta=&aq=f&oq=Safe+mode&fp=1
read up on safe mode if you want.
4. In safe mode run driver sweeper and search just for ati drivers. well u can do nvidia. but if it fresh pc they shouldnt be there!
5. Then pc will want to reboot. Do so then run the setup of the drivers in question and install. Reboot y bobs you aunt and jane's your uncle
Shouldnt take more than 10mins.
Right for the nvidia guy you can do the same sort of thing but use device manager and goto where it says your gpu and then uninstall it.
Then reboot and sweep for nvidia only. Reboot and try 181.22 as these drivers I think for nvidia gpu are best. But I know it's crap if you have to use old drivers when perhaps you want to play avp or mass effect2.
Usually ctds with nvidia cards are either the drivers or new updates are interefering with any mods. If you have old mods installed then there is an update you might have to delete your script file, which is sometimes a hidden file located on your c drive in approaming. Or that etw is coded poorly
But all in your cases making sure your dx is uptodate along with net framework/c++ runtimes is a good idea. Also latest physx.
http://downloads.guru3d.com/nVIDIA-PhysX-System-Software-9.09.1112-download-2442.html