Hi, I have suffered the same problem with (what turned out to be) tsassist.exe. This little beuty resulted in all my browsers being hijacked by some stuff called Dojo and SearchGoI. It was offering Skype updates at the time. I got rid of them but it has re-appeared offering updates to Audacity, CCleaner and others.
I have maneged to get rid of it again with some help from InBay, the support company I use, but I am not convinced this is a perfect fix.
First, can I ask a favouur? If you guys do get to a definitive fix that can be handlednby mere mortals like me, could it be published in some way on Bleeping Computer? I'm a BC newbie, so I'm sure you do this as a matter of course.
Second, tsassist seems to be a product of Avant software. If this is a supposedly legit software company, whose product is helping to distribute malware, shouldn't we be naming and shaming? I may be being unfair or premature, but they seem to be the culprits. All views and guidance (newbie, remeber?) welcome