We are a malware removal site and do not offer troubleshooting support. As you have no access to Windows, there is not much that we can do to help you resolve your problems. It is possible that something went seriously amiss when AVG attempted to deal with what it perceived to be a virus. Perhaps a vital file was corrupted in the process, or a hardware problem may have coincidentally shown itself at that same time.

If worse comes to worse, your hard drive can be removed and slaved to another computer, which will then permit you to copy your important files to other media. In any case, what you need is a troubleshooting site to either get your computer booting up again, or to help you retrieve your data. Otherwise, you will need to avail yourself of a trusted local computer repair shop.

For a troubleshooting forum, I would suggest a site like WhatTheTech:

http://forums.whatthetech.com/forums.html

As this issue requires technical/troubleshooting services and therefore falls outside the scope of this forum, this topic is now closed.