Is this issue present in another keyboard?

If it isn't, Can you try to start Firefox in Safe Mode to see if Firefox works properly with no error? You can start Firefox in Safe Mode below:

• Windows/Mac: Go to Help > Restart with add-ons disabled
• Linux: Run firefox -safe-mode in the Terminal/Konsole

If Firefox opens up fine with no problems, it's probably one of your extensions that's causing the issue. You can re-enable your add-ons one by one until you find the one that causes the issue upon being re-enabled.

I have a laptop, i have try with the keyboard integrated virtual keyboard.

I tried safe mode and it still does not work. I also reinstalled firefox but the problem can't stop.

I am on Windows XP

Can you send me your troubleshooting information from the Firefox installation that's having issues? This is a good part in troubleshooting.

• Navigate to about:support via Address Bar
• Click the button that says Copy text to clipboard
• Now, go back to your forum post and click inside the reply box. Press Ctrl+V to paste all the information you copied into the forum post.

I can't write "about:support" in the Adress Bar, my keyboard don't work.

I can't paste a message in the Adress Bar

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

I don't understand ! I have close Mozilla and open with (windows+R) and i can write !

Really, i don't know what happened, but i'm very happy.

Thanks for your fast answer !!

Some have reported that pressing F9 and the Windows key simultaneously one or more times has worked to fix issues with the keyboard not working.