I have been told by my then Hewlitt-Packard warranty people that an attempt to keep two different antivirus programs on the same disk is a recipe for disaster, and that before installing one antivirus you have to remove the one on the disk. You might check if this is so and applies to your situation. But don't go removing things just on MY say so.

You seem to have Windows. If you tell us which Windows program, it helps.