With Windows XP, as Administrator and sole user, I have at last discovered that Omnipass is listed in Control Panel. But it is not listed among programs, or in Add/remove programs. PerfectUninstall will list it, but will uninstall it only if I register--for 39 dollars!
Perhaps it's not doing as much harm as I suspected--not 39 dollars' worth! UninstallGold might do the same, but the seller is regarded as of unproved trustworthiness! One feels like a shorn lamb.