Use msconfig to make sure that no unnecessary programs are starting up with your computer. To pull up msconfig, simply click start, and type “msconfig” into the search box and press enter. You will be greeted with the msconfig utility. On the startup tab, uncheck everything except your antivirus program and hit apply/ok, and restart your computer. You will likely notice a much faster startup time.
Review your virus protection. And by review I mean have a look in control panel > installed programs and make sure that multiple anti-virus programs are not running. Multiple anti-virus programs will recognize each other’s signature and flag innocuous files as infected. In this way, anti-virus programs will fight each other to the death.