System is Ubuntu 10.04.
I use Firefox for web browsing, I then close it to do other work.
If I then try to reopen Firefox I get an error message;

"Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process or restart your system"


I cannot find a way to close the Firefox which is not responding and therefore have to shut down the PC and start again.
Has anyone else got this problem and /or a solution?
Thanks Cliff

Yes, often, but you don't need to restart PC to close one ordinary application. You can "kill" it. Run terminal and give command: If it will not be killed in few seconds, you can check this with (which will give you PID if firefox is running or nothing if not), you can do force kill it with Forgot about solution: try to be upgraded to newest version (Ubuntu and applications), where errors or problems are repaired. Lastly I haven't problems with Firefox and I am using 11.04.

1 members found this post helpful.

Thank you eSelix
Cliff

You can also try the ctrl+alt+esc key combination

Thanks Fintan69 but ctrl+alt+esc does not work.
if I choose ctrl+alt+Enter it clears the screen but does not clear the obstacle.
The pkill firefox command suggested by eSelix is a complete answer.
I suspect that an even better answer is his/her suggestion to update to a later version.
Thanks to all
Cliff

For what it's worth, there is yet another way to kill firefox:
In linux there is often more than one way to skin a virtual cat!

If firefox is freezing or hanging often, you can try running firefox with a new profile in order to rule out a corrupted profile as the source of the problem. Simply close firefox and then launch it from the terminal with a new profile like this: You will be given the option to create a new profile.

You could also try disabling all of your firefox addons / extensions. Then re-enable them one at a time to try to rule out a rogue addon as the source of the problem.
You could also try renaming your ~/.mozilla directory to ~/.mozilla.bak. Then restart firefox. This will create a brand new pristine ~/.mozilla directory.
You can always go back to your original ~/.mozilla directory (and your original profile) simply by changing ~/.mozilla.bak to ~/.mozilla:
Many firefox troubles can be traced to a corrupted profile and or a rogue addon or two. This can help you troubleshoot and rule out those problems.

Whatever works. I meant ctrl+alt+esc not ctrl + al + enter.