First eliminate any spyware.
What You Should Know About Spyware
http://www.microsoft.com/athome/security/spyware/devioussoftware.mspx

CAUTION!!!!!  Removing some spyware can damage the Winsock stact.  Before
you try to remove spyware using any of these programs , download a copy of
LSP-Fix - a free program to repair damaged Winsock 2 stacks (all Windows
versions)
http://www.cexx.org/lspfix.htm
Winsockfix for W95, W98, ME, NT, 2000, XP
http://www.tacktech.com/pub/winsockfix/WinsockFix.zip
Directions here:   http://www.tacktech.com/display.cfm?ttid=257
WinXP:
Get WinSockxpFix
http://www.spychecker.com/program/winsockxpfix.html
How to Reset Internet Protocol (TCP/IP) in Windows XP
http://support.microsoft.com/kb/299357
In WinXP SP2: You can fix Winsock by going to Start | Run and typing
CMD
In the command window type
netsh winsock reset

See
Dealing with Unwanted Malware, Parasites, Toolbars and Search Engines
http://mvps.org/winhelp2002/unwanted.htm

Note that AdAware and SpyBot S & D will each catch some things the other
won't.  Also, each needs to be updated with the program's update function
before every use, even when just downloaded.  There's also a lot more to do
than just those two programs.  CWShredder is also available here:
http://www.intermute.com/products/cwshredder
**Post your HijackThis log to
http://forums.spywareinfo.com/
http://forums.tomcoyote.org/
http://castlecops.com/forum67.html
http://www.wilderssecurity.com/ or the Spyware forum at
http://aumha.net/viewforum.php?f=30 for expert analysis, not here.**
Alternative download pages for Ad-Aware, Spybot, HijackThis and CWShredder
may be found on this page:
http://aumha.org/a/parasite.htm.

See this link for information about malware:
http://arstechnica.com/articles/paedia/malware.ars

If nothing there helps, please post back to this thread.