Go to Start > Run msconfig
Click the Services tab and uncheck both AVG services (and leave Ewido unchecked too)
Reboot and see if there is any change. Do not connect to the Internet while AVG is unchecked.
See if it helps the speed any. Then go ahead and go back into msconfig. Click the services tab and re-check both Ewido and AVG. Let me know how it goes, please.