I.E. Changes to 8 bit color

[dullfun]

I hate I.E and only use it for certain websites. The problem is that lately everytime I open it, it changes my system to 8 bit graphics and returns to 32 bit after I exit. I installed I.E. 7 to see if that changed anything but no. I have XP sp2 with a 2.8GHZ system. It has never done that before and there is no adware, virus or spyware. I run the latest and best to catch any crap. Any help would be greatly appreciated. Thank you