We're sorry to hear that your Firefox seems to be crashing when you open it. Please perform the following steps to give us a crash report ID that helps us find out more about the cause of the crash.

1. Press the following shortcut to get a Run window: [Windows] + [R]. This should bring up a window that contains a text field.
2. In that text field, enter %APPDATA% and press Enter. An explorer window should open.
3. From that explorer window, double-click on the Mozilla folder, then double-click on Firefox and then on Crash reports. Double-click on submitted.
4. Now, you should see a list of files that contain reports. Go to View > Arrange Icons by > Modified to get the most recent files at the top of the window.
5. Open the most recent 5 files with a text editor and copy the IDs.
6. Paste each ID 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.

Will Firefox start up to the built-in Profile Manager? This will allow you to create a new Firefox settings folder (Firefox profile), after which you can migrate key data. Inconvenient, but possibly necessary.

From the search box on the start menu:

firefox.exe -p

Then click Create Profile to start up in a factory-fresh configuration. This article has the full run-down: Profile Manager - Create, remove or switch Firefox profiles.

See Recover important data from an old profile for information on copying over key settings files. Of course, you should be somewhat selective and not reproduce the problem...

Thanks for the reply unfortunateely this is the only file there InstallTime20120713134347 no crash reports at all?

Thanks, tried this one but it crashes before it will allow me to put in or adjust a profile?