AVG Antivirus

Ive been using avg free antivirus for a couple of years now without any problem,it updates itself and once a week does a complete scan of pc.However,recently it has started running the complete scan every night and i can not change settings.Scan lasts for 2 hours and slows down pc,does anyone have any idea why it is doing this and know how to stop it..

I've put that AVG on a few PCs (although not my own I might add). As far as I've seen (quick look) I've not been able to set it up to do anything but a scan every day. I think that's how they get you to subscribe - by making you scan every day (so that you can stipulate when the scan takes place). You certainly don't need to scan every day.