Clearly this statement says it all, your system has been compromised, AVG could not have fixed the issue as you say there is a screen on your opening page that tells you your computer is infected.
"My avg8.5 says its all ok but I cannot get on the internet I cannot access any files, there is a screen on my opening page that says my computer is infected with a virus??"...
what I would do is shut your system down,
boot up into safe mode and run your AVG again.