I installed Advanced System Care to try to change my settings for Aero Peek. Now I have this rendering bug in my taskbar. I can't seem to undo the changes I've made and I get this every time - how can I fix this bug?
Based on your comment, it sounds like you installed some third party system cleanup/optimization utility. This is always a bad idea, and now I think you can see why.
The easiest fix is probably just a System Restore to before you did anything.