It would help to know..
Your post is short on details. If you have no success accessing System Restore by temporarily disabling AVG (if still installed) as digger suggested, or booting to safe mode with a command prompt, some additional information might help.
It would help to know which operating system you're running. And the names of those 'six infested files'. The names of the one's AVG removed AND those it couldn't remove. Malware has been known to block System Restore.
What security software was in place prior to installing AVG? Or still is?
It would also help to know if you are sure those are the ONLY 3 programs you can't open.
Under certain circumstances the System File Checker (sfc /scannow) might help. While other's, running the Rkill tool might do the job. The above with some background information, might help narrow-down what we think to suggest.
Keep us informed..