I cannot start Firefox but it is running according to task manager

I cannot start Firefox but it is running according to task manager

When you open your task manager you would probably find a Firefox.exe in the process list but you would not see one running on your desktop, just right click on the firefox.exe and click on "End Process" (task manager) or "Kill Process" (process explorer). That should halt the unexpected Firefox and allow you to start a new copy that's visible.

An alternative is to use command line most probably the SysInternals utility called pskill which can be downloaded for free from Microsoft.

Once you have the tool, then in a command shell you can enter the following command:

Pskill Firefox

That should result in something like this:

PsKill v1.10 – Terminates processes on local or remote systems
Copyright (C) 1999-2004 Mark Russinovich
Sysinternals Windows Sysinternals 

Process Firefox killed.

If more than one copy of Firefox was running, that would be terminated as well. In fact, any program with "Firefox" in it's name would be killed. And of course if no such process exists it does nothing. Or you can just shut down your computer and restart again.

Or you can just shut down your computer and restart it again.