Download "Safe", and put it in your startup-sequence or user-startup. Quietly it will scan memory during boot and report to you if it finds any virus on your system.
Its not a complete anti-virus like VirusZ or VirusChecker, but it will search and kill any viruses in memory it finds.
Its good specially when you want to kill the viruses after playing a non-dos game and before it attack your session of Workbench and of the programs in the WBStartup folder.
Many viruses start infecting the programs it finds on the C directory and on the startup-sequence file. So if you attack them since the beginning on the boot, there is more chance for you to "win".