If you are unable to save, copy or move any of you files, and you want to save any important files/data, best option is to boot up on a "Live" cd. (There are several available for download on the web) and do it from there.
You can transfer them to a CD or create a seperate partition and save them there.
I haven't looked at the details, but I do recall reading that AVG9 has been causing some problems in Windows 7. TRy Torrentg's tipo and see if that works.
Another possible saver might be to create another user and see if it has the same problems.