Color Quality

The other day, I was having problems with EDow.exe. I went to a few websites and tried to figure out a way to rid my computer of the problem with EDow.exe. I ran "Hijackthis" and filtered it through a "Log Analysis." I deleted what it told me I should. I ran Hijackthis a few more times to make sure everything was gone. For some reason though, I am now having a problem with the Color Quality found in the "Display Properties" for my computer (which is a Dell Inspiron 8600 with Microsoft XP Home Edition). When I start my computer, it defaults to "Low (8 bit)," when it used to be "Highest (32 bit)." Plus, as I use the web, it periodically reverts back to "Low (8 bit)" after I have set it at "Highest (32 bit)." Can someone please tell me what seems to be wrong from my description? Did I possibly delete something that was needed? If more information is needed, please let me know. Thank you for your time.