Since this issue also occurs in other programs on your system, it is not a Firefox specific issue.

I would recommend reinstalling the drivers for your keyboard. I would also recommend checking your firewall and/or antivirus and Kaspersky settings in order to ensure that these tools are not limiting programs' access to input devices.

If that doesn't help, I would highly recommend contacting the Microsoft support team for assistance with this issue.

Dear Wesley,

Thank you for your prompt reply.

All my applications except Firefox and Chrome, including Edge, are accepting keyboard input, which is puzzling as to why these two are not.

I have two Wintel machines using the same keyboard-wireless mouse combo through a USB switch, Antilogger and Kaspersky are on both. On the one upgraded to Win 10 via Win 7, Firefox is working correctly. So I am looking at my settings on the other one, which was a direct install of Win 10 from a retail disk.

{Does Firefox talk to, or need, Quicktime for Windows? I have a vague memory of seeing something in a forum about a similar problem to mine recently, but the Firefox which works does not appear to have Quicktime installed on the same platform. Revo cannot see it anyway, and Installing it on the other platform does not appear to alter anything as far as Firefox is concerned. I'm asking, just in case, grasping at straws.}

Regards,

The Quicktime plugin is not essential to Firefox and the browser will operate properly without it. Quicktime is a video player developed by Apple.

As for your issue with the keyboard, please try running a scan on your system for malware or other infections. Although you have Kaspersky installed on your system, antivirus programs cannot detect all infections and some of them miss certain infections.

You can try these free programs to scan for malware, which work with your existing antivirus software:

• Microsoft Safety Scanner
• MalwareBytes' Anti-Malware
• Anti-Rootkit Utility - TDSSKiller
• AdwCleaner (for more info, see this alternate AdwCleaner download page)
• Hitman Pro
• ESET Online Scanner

Further information can be found in the Troubleshoot Firefox issues caused by malware article.

Did this fix your problems? Please report back to us!

Do you use any security software with anti-keylogger functions? Some of those programs may not be compatible with Firefox because they modify the keycodes sent to Firefox in a way it doesn't understand. (The one that has been mentioned in the past is ZoneAlarm, but that one scrambles what you type, it doesn't disappear completely.)

Dear jscher,

I use Zemana Antilogger, but I have almost the same setup on my other Wintel machine, and Firefox works fine on that.

All my other apps work fine, only Firefox and Chrome do not respond. (I only put Chrome on, desperately trying to log onto the net other than by Edge, which, ironically, works correctly.)

Thanks for the reply, Regards

Dear Wesley,

Thanks for the follow up, I'll chase down those links.

Regards,