"Avast authorization" won't accept password?/can't uninstall (Avast Free)

Hi,

I have Avast Free and a few days ago it suddenly started asking me for the password - whenever I click on the icon it shows a window with this text:

“Avast authorization: An attempt has been made to enter a protected area of avast! (general program access). This may be a legitimate action, but could also be the result of a malware attack. Do you want to continue?”… and there’s a box for password, and “OK” and “Cancel” buttons.

Without password I can’t access Avast in any way, not even to run a scan.

I ran Malwarebytes full scan yesterday and it found 2 bugs… the computer seems to be clear now, everything apparently works fine (even Avast), but I’m suspicious about this password-thing, thinking there still might be an infection somewhere.
I do have a password from the last registration, but when I try it, Avast says it’s the wrong one. (Now, I allow it’s possible that I’ve messed up while writting down the password and that it is indeed wrong, but I honestly don’t think so.)

I’ve just tried to do the uninstall/reinstall of Avast (following very thorough instructions I’ve found here on the forum), but it won’t allow me to uninstall in the first place - it’s asking me for the password again (that same “Avast authorization” window appears).

I don’t know what to do next by myself, if anything at all (except taking the laptop to a friend who’s into IT to see if he can help). I’m pretty much a newbie when it comes to this stuff, just an average home computer user.

I’d appreciate any and all suggestions, thanks.

Restart your computer in safe mode and run the avastclear.exe to remove Avast then reinstall it. I cannot give a link but should be found in the Avast free, pro, suite section under the Avast program update 2014.9.0.2013 topic.

I have already downloaded avastclear, found it in uninstall instructions. Thanks, will do this and report back with results.