Take a look at this site for a tutorial on spyware
http://www.greyknight17.com/spyware.htm This is a pretty good explanation for the process to follow to clean off your PC, you can just follow the steps. It will take you a few hours since it requires downloading the programs, scanning your drives, and multiple reboots. But once you get it cleaned off, it is easy to maintain. Just run through the steps once a month or so with the latest definition files.
Also, go to this forum
http://www.techsupportforums.com/ and scroll down to the 'Security Center' section for more information. Go into the 'HijackThis Log Help' forum and read the 3rd thread titled 'Please, Read This Before Posting A Hijackthis Log'. If you are still having problems, you can post your log file in that forum and someone will be able to explain what to do.
Here are the links to some of the tools you will need.
Trend virus scanner -
http://uk.trendmicro-europe.com/enterprise/products/housecall_launch.php
AVG virus scanner -
http://free.grisoft.com/doc/2/lng/us/tpl/v5
CWShredder -
http://www.greyknight17.com/spy/CWShredder.exe
Ad-aware SE -
http://www.download.com/Ad-Aware-SE-Personal-Edition/3000-8022-10308605.html?tag=lst-0-2
Spybot S&D -
http://security.kolla.de/
HijackThis -
http://www.greyknight17.com/spy/HijackThis.exe
Also, have you been updating your OS system files with Windows Update? Have you upgraded to Service Pack 2?
And finally, if you have not updated your ZoneAlarm lately, here is the link to the latest version.
ZoneAlarm 5.5 -
http://download.zonelabs.com/bin/updates/znalm/za55062004AEN1023_US.html