Uninstall McAfee Using
McAfee Removal Tool. Uninstall AVG using
AVG Remover. It is very bad to have two antivirus programs installed at the same time.
Use
Microsoft Security Essentials as your antivirus with windows inbuilt firewall, and
free MBAM as the on demand scanner.
Download and install those, and then run full system scans with both of them, one by one.
Update your ATI/AMD display driver.
You can get it from the link in our forum,
Latest AMD Catalyst Video Driver for Windows 7, or you may go to
AMD Graphics Driver and Software and opt for Automatically Detect and Install the appropriate driver for your card.
During installation, you may opt for advanced installation, and install the display driver only, not the Catalyst Control Center.
Let us know the results.