I use this computer for surfing dfwstangs and doing business related tasks, and my wife uses it for the same as well as playing a game called "Ultima Online". Yesterday, this messenger thing started popping up, and I've gotten 5 or so, since then. These things are here when I log-on...What is the deal?

I used that "Hijackthis" but it's not finding anything. Is this a virus or something?

I just don't get how it would happen! Nobody has been to any bad sites or anything! anyway, here is a screen shot...
https://www.dfwstangs.net/hosting/STANGGT40/untitled.jpg
if anyone knows what to do, please let me know! i have no clue how to fix this crap!
thanks,
brad