First off, keep everything up to date.. use windowsupdate.com to get IE security patches and keep a good virus scanner. A free online scan can be done at http://housecall.antivirus.com

Secondly, never get a file with an extension of .url, .htm, .html, .js, .vbs, .vb. Watch for the common spam files -- usually very small and return with a quote from your search..

Fakes I see a lot ::
!!--!! something
!! something
!!! something
!! Free! - something
Free -- something --