Welcome to the forums gadfell2,
Please try using avast's repair function via:
Windows Key+R > Type in: appwiz.cpl > Select avast! antivirus > Click Change/Remove > Scroll down to find the Repair function > Click Next > Complete all the prompts and proceed to reboot.
If above does not work, please take time to answer these questions:
(1) What are you PC's specs?
(2) What is/are your current antivirus(es)?
(3) What is/are your previous antivirus(es)?