Hi
we're shooting in the dark here
did you ever have another AV on this computer or one preinstalled? What OS? Firewall?
especially McAfee, Norton,AVG, Panda, ANtivir?
before you reinstall AVAST (recommended) or any other AV you have to be squeeky clean
or "unpredictable results" follow
go here
http://www.pchell.com/virus/uninstallantivir.shtmlgo to the very bottom of the page and follow the links to any other AV and uninstall
If AVG there is a new AVG uninstaller on the AVG website since PCHell posted
THEN
come back up to the middle of the
http://www.pchell.com/virus/uninstallantivir.shtmlpage
HERE
"What if Windows Security Center Shows AntiVir or other muliple Antivirus products installed"
and follow all of the instructions and links on the rest of the page (even if you have never had ANTIVIR)
One quirk with AntiVir causes it to still show up in the Windows Security Center even when its been uninstalled properly. If this is the case, please refer to this article to resolve it.
http://www.pchell.com/support/multiple_antivirus_in_security_center.shtmlUsing the AntiVir Registry Cleaner-- (works with any AV)
If for some reason the normal uninstall does not work, you may have to download AntiVir's registry cleaner utility to remove all traces of it from the registry and allow you to reinstall it.
1) Click on the following link and download the AntiVir Registry Cleaner to your desktop
http://dl.antivir.de/down/windows/registrycleaner.zip2) Create a folder on your desktop called Antivir and Unzip the file to your desktop
3) Double-click on the file called RegCleaner.exe to run it
4) Since the program is German, you'll have to click on the button called "keys asulesen" to search the registry for any issues. Then place checkmarks next to the registry entries you wish to delete.
5) Finally, click on the button called "loschen" to delete the keys
6) Restart your computer and try to reinstall your antivirus