Anyone getting Pop-unders when you dont have a browser open? I think it may be AIM!!

2 days in a row, i have gotten a pop-under for some computer optimizer program. The pop-under itself looks like the program, but is just a pop-under. Both times I either had my own site open, or nothing at all.

For some reason I suspect AIM. It has been the only program open at the time. Anyone else getting this???