Well done to you for hanging in there.
I really should have solved this one more quickly... when I look back on your computers logs there were signs there, although, it did take a bit more than usual to get the beggars in the end.
but I will certainly be making a donation when I get the money next week
Not necessary but very kind and it does keep the encouragement up.
For the future don't forget the suggestions I made at post number 15.
One further thing I might sugest in this case is; have you tried running Microsoft Security Essentials on your machine? If AVG suits you then stay with it but I have found that MSE together with the Windows Firewall which is already on your computer works very well. I have it on my Windows 7 machine. That pretty much covers my security requirements although I do update and run Malwarebytes once a week as well.
Microsoft Security Essentials is free:
Microsoft Security Essientials
You would need to uninstall your AVG if you did want to try MSE.
Note: Running two or more real-time anti-virus, anti-spyware and firewall monitors at the same time can cause a conflict. That conflict can result in slow computer performance, error messages, crashes of the programs or other types of failure. You will very likely end up with little or no protection.
Meantime I will keep this topic open for a short while in case any issues develop.