I have been fighting with WINFIXER 2005 (spyware) for a couple of months. I finally stopped the popups. If you are still suffering with WINFIXER, you may try the following to get rid of it.
1. download Ad-Aware SE, and clean your machine first.
http://www.download.com/Ad-Aware-SE-Personal-Edition/3000-8022_4-10399602.html?tag=lst-0-1
2. turn on your window XP firewall. here is how:
http://support.microsoft.com/default.aspx?scid=kb;en-us;283673
if you do not have XP, you may download Mcafee firewall software, it is free for camcast users.
http://www.comcast.net/security/mcafee/
3. if you need a help, email me at jingao@comcast.net
I am glad to share my experience with you.