Could you check your actual Firefox version here: Help &gt; About Firefox The forum recorded version

Could you check your actual Firefox version here:

Help > About Firefox

The forum recorded version 10, which is obsolete and insecure, so if that is correct, you should update ASAP. If there is something holding you back from updating, what is it? There may be a solution.

If you do have the current version of Firefox, this article might help: How to reset the default user agent on Firefox.