Check that Firefox isn't set to run as Administrator.

Right-click the Firefox desktop shortcut and choose "Properties".

Make sure that all items are deselected in the "Compatibility" tab of the Properties window.

• Privilege Level: "Run this program as Administrator" should not be selected
• "Run this program in compatibility mode for:" should not be selected

Also check the Properties of the firefox.exe program in the Firefox program folder (C:\Program Files\Mozilla Firefox\).

sir, when i install the mozila it shows you may not have the necessary permission to use all the features of the program you are about to run. you may run this program as a different user or continue to run the program as the current user . but when i choose current user , it gives no response means next step not show.

Reinstall it, but this time install it as administrator by right clicking setup -> run as administrator.

If problem persit redownload firefox from this link http://www.mozilla.org/en-US/firefox/new/

Hope it will solve the problem