Hi Tacobell,

  1. If you’re using WinXP you can use the add remove programs, when you click on the avast program you will see a few options, you should chose the Repair option. You will need to be online to complete this. If you are not using WinXP I think you are only left with option 2 below.

  2. If that fails uninstall, reboot and reinstall.

HTH David