Attempting to treat the symptom(s) instead of addressing (eliminating) the underlying cause, without full success could be in play here?
(They should instead supply the customers with a link to their full uninstallation utility (which removes all remnants of, including registry entries) and offer a refund for paid versions, at least on a pro-rated basis, IMHO).
The beauty of eliminating the underlying cause is that the associated symptoms involved will not have to be addressed again in the future, at least concerning the use of invited 3rd party viruses' (oops, I meant 3rd party Anti-Virus applications, oh yea,
pretty much the same thing, never mind:>)
The Same Old Story, can become exhausting.
Best Regards,
-Richard