Tim, don't delete it - I think you've had a spyware attack. I don't see anything like what you report.
Googling does suggest that it's spyware - CoolWebSearch, possibly. Even searching for it was dangerous, one website I looked at made NAV light up, although I would hope that an IE hijack wouldn't translate to Opera anyways. I'll wait for Richard and Liam to come along, but for the meantime, have a look
here.