If you don't know that you are having any, chances are very good that you are not.
http://www.malwarehelp.org/symptoms-of-infection.html
http://www.microsoft.com/windows/ie/community/columns/malware.mspx
http://www.malwarehelp.org/symptoms-of-infection.html
http://www.microsoft.com/windows/ie/community/columns/malware.mspx