I have Vista Home Premium. I have been trying to delete Grisoft. The screen says I need special permission. I have tried to access the screen for special permission but I have never been able to put a check mark by special permission.What I am doing wrong?

Are you logged on as an administrator?

For uninstalling programs I recommend using Revo Uninstaller.
Does a much better job than Windows.

http://www.revouninstaller.com/revo_uninst...e_download.html

Also, do you have something in mind to replace Grisoft? You'll need to have it downloaded and saved so you can install it right away.

I presume you mean Avg?
Have you disabled it before trying to uninstall?

AVG has been disabled and another antivirus program was installed.I still could not delete all of the AVG files without special permission.

I'd expect that you'd have to take ownership of the files before being able to give special permissions. But since you're going to delete them, once you've taken ownership you should be able to delete them anyway.

Right click on the file and select Properties, then click on the Security tab, then on the Advanced button
Then click on the Owner tab, then on the Edit button.
Then double click on your user name, then click on Apply, then on OK in order to take ownership.
Exit the dialog and you should be able to delete the files.