Tell your friend to try the advice on this link from the AVG website.
Copy and paste the whole link into your browser and then take the space out between the http:// and the rest of the URL. I had to put that in there because of the CNET spam filter with the word ''free" in it.
My friend says that every time he updates AVG he has to restart. I don't experience that. Should he remove and reinstall it? He is using version 7.0.344 as I am.