Do a malware check with some malware scanning programs on the Windows computer.
You need to scan with all programs because each program detects different malware.
Make sure that you update each program to get the latest version of their databases before doing a scan.

• http://www.malwarebytes.org/mbam.php - Malwarebytes' Anti-Malware
• http://www.superantispyware.com/ - SuperAntispyware
• http://www.microsoft.com/windows/products/winfamily/defender/default.mspx - Windows Defender: Home Page
• http://www.safer-networking.org/en/index.html - Spybot Search & Destroy
• http://www.lavasoft.com/products/ad_aware_free.php - Ad-Aware Free

See also:

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

Cor-el,

Thank you VERY much for your advice. At first I blamed Firefox 8, but other problems showed up as well today. A full system scan by first Symantec antivirus and then by Malwarebytes found a number of infections. After they were removed/quarantined, the problem with Firefox redirecting from Google search to the wrong site is fixed. Other problems as well.

I'm concerned that there may still be rootkit-delivered malware such as TDSS lurking in the machine, so tomorrow I'll run TDSSKiller and see if it finds anything.

But mostly I want to apologize for blaming the problem on the upgrade to Firefox 8. The Google search redirection problem seemed to show up at the same time, and it seems clear that I incorrectly associated the two.

Martt

You're welcome

cor-el,

Several additional observations which may be relevant:

1. The finger of suspicion seemed to point at Firefox 8 because IE7.0 didn't display the same symptom of redirecting Google search to the incorrect website. IE7.0 appeared to continue functioning normally.

2. When I ran a full scan using Symantec 10.1.6.6010 yesterday evening it found about 30 infections. Among them was the immediate cause of my annoyance, an infection that presented as "XP Home Security 2012". May have been Trojan.Gen.2 which showed up in multiple copies. Symantec also found the Windows firewall turned off, which may have been my error but I'm pretty careful about keeping tools like that, active. It's on now. However the problem with Firefox 8 remained. I can supply the Symantec scan results if that would be helpful.

3. Then I ran MalwareBytes Anti-Malware. It found about 5 infections and cured them. That fixed whatever was causing the problem with Firefox 8. I can supply the MalwareBytes log if that would be helpful.

4. A scan this morning with Kaspersky's TDSSKiller didn't find anything.

Martt