Hi,
please go here: What version is here: c:\ProgramData\AVAST Software\SZBrowser\profile\[YOURUSERNAME]\Extensions\
Rightclick the blgbpiedcngldakfgncemilphjcmnmio folder with your mouse, choose preferences -> Security tab -> Select your user name (if there is any), Attach screenshot of it.
Also Go to start menu and search for User Account Control Settings. Tell me what is your settings.
Thank you