First, try to reset Firefox. Refresh Firefox - reset add-ons and settings. This simple step will eliminate many Firefox problems with only one click.

Download and Install MalwareBytes Anti-Malware, run a full Scan. http://www.malwarebytes.org/. This helps check that there are no viruses on your computer causing issues. You can uninstall this program after you clean off any infections.

After doing these steps, go ahead and update to Firefox 14.0.1.

Tried all this - looked for malware etc etc - removed some (not associated with btsearch) no luck.

In the end:

Tools Options General Startup see btsearch as your Home Page. Delete it and replace with your own preferred web page

I suggest that you visit a website specializing in malware removal. See Troubleshoot Firefox issues caused by malware

Here is a recent post by a Firefox user with a similar problem in the Bleeping Computer forums (do NOT follow those instructions, which are specific to that user. It's just an example of type of help you can get there):

• http://www.bleepingcomputer.com/forums/topic479906.html I can`t stop http://btsearch,name From being my homepage !