Can you post a screenshot of the message? It may be asking for the password for your Firefox account.

OK, tried a heap of passwords and an old Apple ID password got me back in, Firefox then crashed. Only locked me out when computer was asleep so will see how long till the net one.

We're sorry to hear that Firefox is crashing when you open it. Please do the following to give us crash IDs that will help us understand more about the crash.

1. (OS X 10.6 or previous) Click the Finder icon in the dock. Your home folder will be selected. In the right side of the window, click the Library folder to open it. Then open the "Application Support" folder, the "Firefox" folder, the "Crash Reports" folder and finally the "submitted" folder.
   (OS X 10.7 or above) Click the Finder icon in the dock. On the menu bar, click the Go menu, hold down the option or alt key and select Library. A window will open containing your Library folder. Then open the "Application Support" folder, the "Firefox" folder, the "Crash Reports" folder and finally the "submitted" folder.
2. Open the 5 most recent files with a text editor and copy the IDs.
3. Paste each ID with bp- into the reply window on the forums.

Thanks in advance!

You can find more information and troubleshooting steps in the Troubleshoot Firefox crashes (closing or quitting unexpectedly) article.

Thanks for your help, there may be another issue. 2 days before the first lock out I witnessed a serious crime in which I recorded the accused and yesterday I noticed all the video from that crime has been deleted from my computer so who knows if this is related. (Did have backup though).