Disable your virus scanner, shut down any programs
(besides explorer) and reinstall windows from your cd.  
You should see a noticeable difference.  Don't forget to
then run Windows Update.  Start with that, it's better
than reformatting from scratch if you don't have to.

Update your anti-virus app and then run a full-system virus scan.

Read here:
Dealing with Hijackware
http://mvps.org/winhelp2002/unwanted.htm
http://www.mvps.org/inetexplorer/Darnit.htm#tshoot
http://aumha.org/a/parasite.htm

http://doxdesk.com/parasite/CoolWebSearch.html
and
http://www.merijn.org/cwschronicles.html

Use CWShredder, the removal tool, available here:
http://computercops.biz/downloads-cat-14.html
http://www.majorgeeks.com/downloads31.html
http://www.zerosrealm.com/downloads/CWShredder.zip

In addition, install Ad-Aware 6 free edition, start it, click its 'Check for Updates' link in the app to install updates, then use it to scan your system, and remove what it finds.
Ad-Aware:
http://www.lavasoftusa.com/support/download/

Install, update and run SpyBot Search & Destroy, scan your system, and then remove the items in RED only.
SpyBot S&D:
http://www.safer-networking.org/index.php?page=download

Download, unzip, and run Hijack This from one of these locations:
http://computercops.biz/downloads-cat-14.html
http://www.majorgeeks.com/downloads31.html
Unzip to a folder other than your Desktop or the Temp folder,  doubleclick HijackThis.exe, and hit "Scan".

When the scan is finished,  the  "Scan"  button will change into a "Save Log"  button.
Press that,  save the log somewhere you can find it (Desktop, My Documents, or similar).
Most of what it lists will be harmless or even required, so do NOT fix anything yet.

Copy the log files and paste them into a new post at one of these forums:
http://forums.net-integration.net/
http://computercops.biz/forums.html
http://forums.spywareinfo.com/index.php?showforum0
http://tomcoyote.org/forums/
http://www.lavasoftsupport.com
http://boards.cexx.org/

The folks there will tell you what to remove.