You are not the only person, try Avast help, they are USELESS, unless you pay them $175
On my Toshiba, I broke the cycle by hitting F12 repeatedly on start-up, then chose my start up.
I have got rid of Grime Fighter
How they can sell a product that claims to FIX issues, that takes total control of your PC is beyond me.
When I phone, 3 times I was told something different, they told untruths, and guess what, they are not Avast, it outsourced. I was told my PC had a malicious program, I suggested that if Internet Security was doing its job, there should be no issues.
I finally had a supervisor from the USA not India, made no difference, just said sorry can't do anything. I have 200 odd days of protection left, then I jump ship