Hello and welcome to the forum.
I assume that by "Avist" you actually mean Avast, and.....
I can't imagine why that would have impacted your keyboard although I've never used it.
Can you use the "Ease of Access" icon on the sign-in screen to bring up the On Screen Keyboard (Osk.exe) and use that to enter your password?
Do you have a spare USB wired keyboard that you can try to see if it provides any different results?