I belive that driver reinstalation only did so mutch to reset your graphic profile of FW. I had exact same problem and traced it down to AA settings (somehow the game retainet AA on even when I forced it to off from the drivers). Once I installed NHancer and made a new profile (it seams that NVIDIA named the exe in her profile kv.exe
) and forced AA to off in that profile, everything went back to normal. Hope this helps.