I would clean reinstall with 32 bit following these steps to Clean Reinstall - Factory OEM Windows 7
Use MSE or Avast 5 with Win7 firewall for least performance hit.
As mentioned the change of AV's along with the use of a registry cleaner likely has corrupted your install. Most other Reg Cleaners besides CCleaner are sales operations with no real genius, which is what you want if you're analyzing the Registry. You may have done other tweaking, too, which is a sure way to mess up Win7 - which will not tolerate compound tweaking.