Elder Scrolls IV Pixelation/Graphics Problem

[JMChurch]

Getting a weird problem with Oblivion. Installed it last night and played for a couple of hours without any problems, but when I started playing this morning i am getting weird graphics problems. The gameplay is fine, but its like the pixelations are missing/screwed up or something. This applies to menus and saves as well as the general gameplay. I don't know how to describe it without taking a screenshot of it, but it's really weird and im not sure if the problem is with the graphics card/overheat/the system or what. I am using a GeForce Go 74000 graphics chip set and I've tested things with the diagnostic tool and it says there are no problems....any thoughts?