car insurance search engines

Every time I try to do a search on Yahoo, it redirects the results to click on an unrelated page. Help?
It's been going on for a month or so now. At first I thought it was something wrong with Yahoo, but now I know it's definitely something on my computer. Might have been the after-effect of some viruses, but I do not have any viruses (including conficker). As an example, I searched for "Sophocles" and click on the address of the Wikipedia and the first address bar became "http://results.yahoo.com" before switching to "http://www.nationwide.com/sem/auto_testimonial. html? CPAO = 127 & CIFA = ROC & CPAG = Auto & KW = U.S. and WT.srch = 1 & WT.mc_id baROC00008 = & engine = & keyword = request baROC00008 " and leads me to a safe car. Who can help? :]
have a virus. Download bytes malware.
Car Insurance.com “Laundry” TV Commercial by Mpower Media