A friend of mine asked me how to disable the auto updater of AVG Free. It's pretty simple; all you have to do is go to the AVG control panel, find "Scheduler" (self-explanatory; it paints itself with a bullseye with a note that says "Check here! Check here!" hehe!) and go to "Scheduled Tasks". There you will find the entries that you need to fiddle with. Click on them and uncheck the boxes that have anything to do with "Automatic Updates".
Why do this? Well it's pretty annoying when you some resource-intensive activity (games, Photoshop, CADs, etc) and your PC suddenly decides to update --- and then goes turtle. Better to manually update. ;)
There are lots of forums and sites that urge you to do this but I first learned this from Tweakguides.com.
AVG free is one the best freeware I have ever stumbled on. It's recommended by numerous PC users and even by two books.