If you want to get rid of those nag screens, just change the permissions on the avnotify.exe file.
Match them to this.
(warning, don't click apply until you are done, otherwise this can get irritating)
Delete all users and add "Everyone"
You need to set the security options for everyone manually, so navigate to this screen.
Find the file, and go to properties
At this point, you may need to click advanced, and then uncheck inherit permissions, you can choose to remove all permissions when prompted. Then close the advanced.
Bottom Left^^^
Now add/remove all users until all you have is the "Everyone" user.
Now click advanced once again
And click Edit
Set the permissions on the Everyone user to match what you see below
Avira will no longer irritate you at every update.
If you are running XP home, you will need to boot to safemode to do this. If your running XP Pro with "Simple File Sharing" turned on, you will either need to turn that off, or use safemode. I have no instructions for Vista so I hope it is similar.[/img]