When I click Start\Program Files\Avast!\Avast anti-virus … Avast! runs through a start-up check for about 30 seconds, following which the screen says “Avast! will now continue.” But it doesn’t continue; instead I am returned to my desktop. What am I doing wrong?
FWIW, I have Avast! installed on my Aptiva desktop with W98.
Can you try to repair your installation?
Go to Control Panel > Add/Remove programs > avast! antivirus > Remove. Then choose Repair function in the popup window (Repair). You must be connected to the internet while repairing.
If this does not help, can you uninstall / boot / install / boot again?