Hi there. I can't help you get rid of it or change it but can offer this advice. Do you have a good anti-virus or even better, Zone alarm (pro)? If not then it may be a dodgy web-site has placed the code for this search engine thing in there without you knowing. Zone alarm is good for preventing this as is Norton. If this is the case then look at putting either of them (pref both) on your system. Also consider Spybot, that is useful for blocking things like this. I think you can also use TweakUI to change your search preferences, maybe have a look at that. Hope this has helped a bit.
Brl.