Because it does remove AVG anti-virus files, folders, registry entries from root automatically in one click.
Scroll down and go to the download link to AVG uninstall tool Download.
We know it sounds odd that you have to be a computer administrator and also select the additional option, but that is part of it now.
after that then just running them like you do normally is all that is used ...its only during the install or uninstall that you take this extra step.This question came up as well in the AVG forums, but sadly, no solution is ever given in these threads.This would in my opinion constitute a pretty serious issue for AVG, if normal users can't even get AVG installed on Vista, that's a pretty major issue, and it certainly was not effectively handled in the AVG user forums in my opinion, I can see that most users when faced with problems like this will just give up and move to some other AV program that does install without headaches.Proceed as normal to update definitions, and run the scan.
I assume this is a permissions problem, let's see...
If you run Windows Updates after installing AVG, the Resident Shield Service will sometimes refuse to initialize.
If you have already installed AVG and are having problems on a machine running Vista, uninstall AVG and run Windows updates.
It is necessary to run Windows Update BEFORE installing AVG Free on a Vista machine.
Without the necessary updates, AVG will not update properly.
This means that during normal installs and uninstalls you need to take an additional step so the programs can install properly.