I have two suggestions:
1- Show your computer to a professional. This is what I recommend.
2- "Unexplained computer behavior may be caused by deceptive software
http://support.microsoft.com/kb/
Viruses and other malicious software (collectively known as malware) can
be very hard to detect, and even harder to remove. Sometimes, malware is
impossible to remove, no matter what you try. (More on that later.)
If you suspect your computer is infected, follow these steps:
1) If you have anti-virus and anti-spyware programs already installed on
your computer, update the programs and scan your computer. With luck,
the programs will detect and remove the problem.
2) If the scan doesn't produce results, contact the program's technical
support. Most of the major anti-virus/spyware programs will help you to
remove an infection that their software did not detrect.
3) Scan your system with /several/ of the better free online scanners,
such as:
Kaspersky Antivirus (
http://www.kaspersky.com/virusscanner)
NOD32 (
http://www.eset.com/download/index.php) - free 30-day trial
Trend Micro Housecall (
http://housecall.trendmicro.com)
Panda ActiveScan (
http://www.pandasoftware.com/activescan)
Sophos
(
http://www.sophos.com/products/free-tools/sophos-threat-detection-test.html)
McAfee Free Scan (
http://us.mcafee.com/root/mfs/default.asp)
Symantec Security Check (
http://security.symantec.com)
Avast! (
http://www.avast.com/eng/avast-virus-cleaner.html)
GrisSoft AVG (
http://www.grisoft.com/doc/34/ww/crp/0)
4) HijackThis (
http://www.spywareinfo.com/~merijn/programs.php) is an
advanced scanner for spyware. You can post its logs to
http://spywarewarrior.com/viewforum.php?f=5 (among other places) and get
expert analysis of what's on your computer.
5) Finally, if none of the above remove the malware, it's time to show
the computer to a professional.
Here's a sobering thought: There may be nothing at all that you can do
to remove an infection, no matter what you try. That's because some
infections compromise your computer to the point where you can no longer
rely on what the operating system is telling you. Rootkits are an
example of this kind of infection. In that case, your only way out is to
erase your hard disk and reinstall everything from scratch.
"Help I Got Hacked. Now What Do I Do?"
http://www.microsoft.com/technet/community/columns/secmgmt/sm0504.mspx
"So how did I get infected in the first place?"
http://forums.spywareinfo.com/index.php?showtopic=60955