If Firefox and other programs are effected, this could be a system or keyboard issue.

Perform a System File Check to fix corrupted system files

Win 7, 8, 10, Vista: https://support.microsoft.com/en-us/kb/929833 Win XP: https://answers.microsoft.com/en-us/windows/forum/all/windows-xp-scan-and-fix-disk-errors/6fe2827a-4be6-4bc1-8083-5139b5aa3a3d

Wiki - Windows 10 System File Check http://answers.microsoft.com/en-us/windows/wiki/windows_10-update/system-file-check-sfc-scan-and-repair-system-files/bc609315-da1f-4775-812c-695b60477a93

Thanks. Hehe.. very interesting... :-) my problem now is that, when running Command Prompt, still my Enter key does not work, so I can not command anything :-//

enterkey said

Thanks. Hehe.. very interesting... :-) my problem now is that, when running Command Prompt, still my Enter key does not work, so I can not command anything :-//

Hello enterkey,

Could you (for now) use the on-screen keyboard, and use the Enter key there (if it works ... ), till it's clear what is causing the problem  ? (sounds like a broken Enter key .... )

https://www.isunshare.com/windows-10/6-ways-to-turn-on-on-screen-keyboard-in-windows-10.html

Thanks. Of course I thought about a broken key, but the think is that both keys Intro and Enter stopped working after re-installing Firefox. that's why I think there's something...

enterkey said

Thanks. Of course I thought about a broken key, but the think is that both keys Intro and Enter stopped working after re-installing Firefox. that's why I think there's something...

I've never heard of an ' Intro key' ..... (?) Could it be that you're talking about the Windows logo key  ?

The Windows logo key (also known as Windows key, Winkey, start key, logo key, flag key, super key, command key or flag)

Have you tried the on-screen keyboard, to see if they'll work  ? And if they do : follow FredMcD's suggestions  ?

Hello. Sorry. Yes, well, I mean Enter/Return/Intro... what I mean is that there are 2 keys: https://en.wikipedia.org/wiki/Enter_key#/media/File:Enter.png Thanks for your reply. So, I have used this screen-keyboard, thanks, and did the system check FredMcD said. I did run it and it says everything is ok. Still, however, enter key not working yet :-/

Would you try this please :

Open the Task Manager (Ctrl + Shift + Esc) and make sure that no applications are running. Then try the Enter key again ….

Done it. Nothing else running. Still enter key not working. I am sure it has to do with the Firefox update I did. Because it's when it started not working :-/

enterkey said

I am sure it has to do with the Firefox update I did. Because it's when it started not working :-/

Does this mean that the Enter key works when you use i.e. Edge (or another browser)  ?

If so : do you have any add-ons installed  ?

Start your Computer in safe mode with network support. Then start Firefox. Try Secure websites. Is the problem still there?

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode Starting Any Computer In Safe Mode; Free Online Encyclopedia

If the problem is still there, ask for help here;

https://support.microsoft.com

http://answers.microsoft.com/en-US/windows/forum/windows_10

McCoy said

enterkey said

I am sure it has to do with the Firefox update I did. Because it's when it started not working :-/

Does this mean that the Enter key works when you use i.e. Edge (or another browser)  ?

If so : do you have any add-ons installed  ?

No, Enter key doesn't work. With any program. Just after updating Firefox, Enter key stopped working, for all the computer, for all the programs. Add-ons: I think now I only have ad-block, as I always have had. But when I updated Firefox, add-ons were supressed, Enter stopped working. Later I have only installed ad-blocker again.