Hello and welcome to Bleepingcomputer.
I read your description above and noticed by the wording you used, that you are saying you originally did not have this issue, but then suddenly this issue did pop up. Does this sound correct?
Did you recently use Windows 7's Performance information and tools
which is found in the control panel menus?
AeroPeak can be disabled within that feature, you may want to go there and see if you can turn it back on.
You may have ran an older program such as an older video game which set your video back to a lower resolution with less colors available at 16 Bit and failed to allow Windows to go back to 32 or 64 Bit color.
I would first try going to the control panel and click the link to Performance information and tools and check the status there, then post back and describe what you see.
Pay attention to the link on the left that says visual effects. That is the one you want to click on.
Edited by MrBruce1959, 07 August 2010 - 11:45 AM.