Wake up problem on iMac

Does anyone know what could be cause my iMac to show the desktop when i move my mouse around after waking from sleep? Kind of looks like aliasing but instead it shows the desktop when ever I move my mouse. I can't close or start a program using the mouse. I'm able to press the power button and put the iMac back to sleep then wake it back up without the problem but when it's been asleep for a while and I wake it up by moving the mouse this problem returns.

I recently installed McAfee and uninstalled McAfee because I thought that caused and would fix the problem. Then I found out a week or so later that I was infected with the flashback trojan.