Cannot uninstall or open Avast

Hello!
So I had a master password on avast and I now cannot remember or access it. I must have had a setting on so that when I restart my PC it locks automatically.
So I have tried to launch avast and I can’t because all I get is a screen asking me to enter my password, the only options I get is: Okay(enter) or Cancel, nothing where I can reset a password.
Similarly I tried to uninstall it so I could re-download it however that isn’t an option either because once again it asks me for this master password which I cannot remember.

Any help is much appreciated!
Kind regards,
Jack

https://support.avast.com/en-us/article/Uninstall-Antivirus-Utility