Firefox is one of the most popular web browsers for use today is overtaking Internet Explorer 9. When you install a version of Firefox, by default, Firefox checks for updatesautomatically to the main application itself, installed plugins, and search engines.Sometimes, however, when you do an important job on the internet a pop up may appearautomatically updating Firefox and interrupts their work. Or maybe you plan to manually update when you have free time. These are the reasons why you might want to stopautomatic updates of Firefox. Currently, all versions of Firefox has an option to stopautomatic updates.
Now I’ll show you how to stop this automatic update of Firefox :
1. Click on the Tools menu and then navigate Options. Click on it.
2. After Options dialog box opens, click on the Advanced Tab and then click on the sub-tab Update.

3. You can see in the above image that all the Check boxes are enabled. Now just uncheck all of them then click OK to stop auto update of Firefox.

very nice post ..& .useful..