mchain
5
Best course of action is to use a friends/family computer and save the resulting large file to an usb stick. Then transfer these two files over to your system.
Be offline as you will have no protection without an antivirus on you system when you uninstall avast! using Programs and Features. Be sure to place aswclear.exe on your administrator’s desktop first after uninstalling avast, click that, and allow your system to reboot into Safe Mode. Run aswclear.exe only in Safe Mode and choose the default settings. Reboot. Once back in administrator account, double-click the full avast file residing in the downloads folder and allow avast to fully install. You should see avast perform a very quick scan when it is finished. Reboot one more time.
Better now?
IMPORTANT: Install this program beforehand to prevent usb malware infections from either friend or family: http://www.mcshield.net/ Be sure it is up-to-date before beginning any usb transfers; use the updater function within the program to do so.