I was speaking to a user on a Poser mailing list who was experiencing the exact same problems. Apparently, it's a form of browser hijacker, similar to those adware toolbars "enhancements" except more malicious. This is one reason why it's good idea to turn off the automatic installation of desktop items in Internet Explorer's 'Internet' Security Zone. Why this is even turned ON as a default setting for IE is beyond me. Stupid M$!