Try the Repair first:

  • Go to Control Panel > Add/Remove programs > Avast Antivirus.
  • Scroll down and choose Repair function in the pop-up window.
  • Reboot.

What other security software do you currently have or did you have in the past on this machine including:

  • Antivirus (AV)
  • Firewall (FW)
  • Trial versions of AV, FW and other security programs
  • Other security software
  • If they were in the past, how did you remove them (the vendor’s uninstaller’s tool or another way)?