Update: 27th May 2012 - If you want to remove AVG Secure Search as your default, these instructions will help - I had the problem with one of the PC's here. It's related to installing the AVG Toolbar but it's not as easy to fix as changing back from Google.com to Google.co.uk which this article is to fix...

Here's how to fix the bug where Mozilla Firefox will suddenly change your default search engine from Google.co.uk to Google.com

Apparently, if, like me, you occasionally search on Google.com but normally use Google.co.uk, it's a cookie issue. The fix is to clear the cache and the cookies from sites that cause problems.

"Clear the Cache":

In Firefox, from the menu (the one right at the top of the screen including: File, Edit, View, etc) select Tools:

• Then from the drop down select Options
• Click the Advanced tab
• Then from the sub tabs click Network
• Go to the Offline Storage (Cache) box and hit the button "Clear Now"

Cool. You're half way there.

"Remove Cookies" from sites causing problems:

In Firefox, from the menu select Tools again:

• Then from the drop down, Options
• Click the Privacy tab
• Then click "remove individual cookies"

• Scroll through this list of folders until you come to the one named Google.com
• Click on this folder (only once)
• Click the button "Remove Cookies"
• Repeat for any other regional variations of Google you don't want to use
• Leave the Google.co.uk folder alone

Fixed. Well, it works in Firefox 7. Variations on this theme will work in other versions is my bet.

Good luck.

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