https://support.mozilla.org/en-US/kb/does-firefox-work-windows-8-and-windows-rt

This is not an answer, Maddy121, I'm sorry to say. The article is not clear on whether we must use Nightly or whether Firefox 21 will work. I was successfully using Firefox 21 for a week before this same thing happened to me. Suddenly, the icon in the task bar indicates that Firefox is open, but it will NOT maximize the window onto the desktop. I uninstalled and reinstalled with no luck. It's very frustrating!

You can use one of these to start Firefox in Safe Mode:

• On Windows, hold down the Shift key while starting Firefox with a double-click on the Firefox desktop shortcut
• On Mac, hold down the Options key while starting Firefox
• Help > Restart with Add-ons Disabled

• https://support.mozilla.org/kb/Safe+Mode

You can check for problems caused by a corrupted localstore.rdf file.

• http://kb.mozillazine.org/Corrupt_localstore.rdf

Create a new profile as a test to check if your current profile is causing the problems.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer some files from an existing profile to the new profile, but be careful not to copy corrupted files.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Cannot even get Firefox to open on the desktop using the <shift> key safe mode process you describe. It just does the same thing. Opens as the task bar icon but does not maximize the window on the actual desktop. It's simply impossible to get it open on the desktop to work on in any way.

It just shows as an icon on the task bar, and when you hover over the task bar icon, it shows a "mini" (very tiny) view of the open Firefox browser, but there's no way to work in it. It will not establish itself on the desktop at all not matter what you click or do.

As I mentioned earlier, I uninstalled Firefox and then re-installed it assuring that it was version 21. Nothing seems to help. Same problem regardless of whether I try to start it on the Start page or on the desktop.