so i just bought a licence for grime fighter i clicked on the link form the email i got i typed in my password, then my internet seemed to crash and it just said link has already been used, then i go to activate my licence and it says valid available usage 1 out of 1 yet when i click use this licence it just comes up with a cross and doesn’t do anything?
it’s the same problem on my pc.
did you solved it?
i tried it in avast support, but no help from them.
I bought the license two times but it works non of them. 
Hi,
Please open the Avast user interface and go to Tools, then Scan for Performance issues.
Once this screen opens (the main GrimeFighter user interface) click “optimize my PC”
You should then be able to boot into GrimeFighter and the cleaning process should begin.
Please post back if this worked on not.
Many thanks,
Davidek