First thing I'd find out is how that BIOS password got there in the first place. Is this a second hand computer? Did someone else with access to the computer put that password there? The reason I ask is because the virus may have infected your BIOS as well... although I haven't heard of a virus putting a password on your CMOS setup. Doesn't mean that it's not possible, however. Computers don't come with a password on the CMOS from the factory... so someone (or the virus) put it there. When you remove the CMOS battery, also unplug the AC power... the battery is only a backup when the computer isn't being powered by AC... so if you have it plugged in, nothing will be cleared.