Do a malware check with several malware scanning programs on the Windows computer.
Please scan with all programs because each program detects different malware.
All these programs have free versions.

Make sure that you update each program to get the latest version of their databases before doing a scan.

• Malwarebytes' Anti-Malware:
  http://www.malwarebytes.org/mbam.php
• AdwCleaner:
  http://www.bleepingcomputer.com/download/adwcleaner/
  http://www.softpedia.com/get/Antivirus/Removal-Tools/AdwCleaner.shtml
• SuperAntispyware:
  http://www.superantispyware.com/
• Microsoft Safety Scanner:
  http://www.microsoft.com/security/scanner/en-us/default.aspx
• Windows Defender: Home Page:
  http://www.microsoft.com/windows/products/winfamily/defender/default.mspx
• Spybot Search & Destroy:
  http://www.safer-networking.org/en/index.html
• Kasperky Free Security Scan:
  http://www.kaspersky.com/security-scan

You can also do a check for a rootkit infection with TDSSKiller.

• Anti-rootkit utility TDSSKiller:
  http://support.kaspersky.com/5350?el=88446

See also:

• "Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked

The reason I restarted firefox was to try to fix another problem I'm having, however. I can no longer search mail in yahoo. When I first restarted firefox, it fixed the problem. But 10 minutes later it's back again.

I recently did some pretty extensive scans, and got rid of a virus called scorecard research. I did a few more, of the ones you listed, and I'm clean so far.

I did want to say that I also installed Firefox Adblocker plus, which fixed my problem with ads in my yahoo mail.I had Adblock plus installed already, but restarting made it go away, for some reason.

I am still trying to figure out the problem with yahoo mail. It doesn't happen when I use internet explorer...