If anyone is having problems with their system and is unfamiliar with Mr. Ghazi's superb site on making friends with their PC, I suggest checking out his awesome site http://www.tweakguides.com/

His Windows optimization guide as well as Nvidia Forceware guide have been invaluable to me when I was struggling with Oblivion. I realized that most of my problems came from my system not being properly set up and optimized to game when initially I cursed developers, modders, friends, and my cat. I've seen some posts in this section that could benefit from his guides. Beware as there are no easy fixes here and it will take time to peruse his site and tweak your system, but in the end it will be worth the effort.

Also he is in the process of working up a new guide for Skyrim. Be on the look out for it.