delay/superfecta,
1. Don't open up email w/attachments, don't click on any pop-up ads no matter how enticing, and stay off undesireable web sites.
2. Download and run an anti-spyware program like SpyBot. Here is the link; make sure to update right away.
http://www.safer-networking.org/index.php
This is not 100% effective, so see #1.
Or try an online scan at
http://www.pestscan.com/
3. Get a pop-up blocker. Haven't found one I like, so perhaps someone else will chime in.
HH