I believe I have a virus on my cpu. When opening up windows explorer It automatically goes to some odd search engine. Now I can go about surfing the web but if I try to log onto my e-mail it sends me back to the search engine unless the security settings in on high. But then I can't delete e-mails and setting it to even medium high will send me back to the search page. Is anti-virus software the answer? If so what is a good one? Also if I bought a windows xp disk could I delete everything and start all over? I have nothing important on my cpu as it is mainly used for games. Thanks.