This problem showed up in early August 2011. If I open Firefox 3.6.4 I get my usual blank page because I have selected that option under Tools>Options>Startup. However when I open a new tab someone shoves a Bing search field on what should be a blank page. I suspect it is Microsoft and I hope Google continues to kick their ****.

Do a malware check with some malware scanning programs.
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

I had already replaced Bing with Google as my default search engine but kept getting Bing on the new tabs, which I found incredibly frustrating.

Finally, I found that I could get back to a blank tab by going to my computer's control panel and uninstalling the Start Now Toolbar. Phew. No more Bing!

Thank you; thank you. You nailed it. No more Bing search tool when I open a new tab. The new tabs are now blank and clean.

Thank you, Alan

Thank you. I did exactly what you said and "bingo" the problem was solved. No more unwanted "BING" search bar.

Pennylain's solution worked ! Thank you, Charley

Thank you - It worked!!!

Uninstall Start Now Toolbar in control panel. I am using windows xp and don't see this option. What am I missing? Thanks