Wow, DS, you've had the worst time of things with computers...
I've used the AVG free version for many years- both at home and in China- and had outstanding results with ZERO problems.
Are you still running Kaspersky or any other virus scanner? Sometimes trying to run more than one can cause things to slow way down. Or perhaps you're running something else that stays resident and is competing with AVG for resources...
Otherwise, there may be some kind of voodoo happening with your university network firewall; these turn out to be the source of many computer mysteries.