May I suggest a different approach?
Download ANEW the setup.exe for the latest stable version of Avast.
Download the removal utility for Avast
http://www.avast.com/uninstall-utility.
Now reboot into
Windows Safe Mode and run the removal utility. Please do NOT run it under Normal Mode, and do NOT use at this time the normal "Add / Remove Programs". Simply directly run the removal utility from Safe Mode.
Then reboot into Windows Normal Mode. DISable *ALL* gadgets. Search for any folder or file which
file name contains the words "avast" or "alwil". The same for any such folder. The only file that should "survive" should be the just downloaded ANEW avast setup.
Right click the setup.exe -> properties -> "unblock" (if the button is available - not grayed out).
Right click the setup.exe -> "Run as Administrator". Follow the installation instructions. When the setup finishes, please reboot IMMEDIATELY.
Avoid configuring avast, the registration or any update
at this point. Simply proceed with the normal reboot.
Once you reboot, configure Avast and update it. Once it is working correctly, please reboot AGAIN.
If Avast now works correctly, only now re-enable all the gadgets. Reboot once more so to test if Avast is being displayed correctly.
Please report back