Hmm that does sound nasty. Let's see if we can't fix this. I might need some further information to help better, if the solutions below doesn't work. I will need to know which options are selected in the crash reporter, and one of the crash reports will also be extremely helpful - don't worry that it is long, useful data about why this is happening can probably be found somewhere in there. See the [[Mozilla Crash Reporter]] article on how to find the reports, section "Viewing reports outside of Firefox" points to where you can find the reports. But first, lets see if we can't get Firefox started without crashing - here's a link explaining how to start Firefox in [[Safe Mode]]. Make sure no Firefox instance is running before starting Firefox Safe Mode- you can check this by pressing Ctrl+Alt+Del to bring up the Task Manager, and under the Processes tab check that there is no firefox.exe in the list. If there is, highlight it with the mouse and Kill the process. Then start Firefox in Firefox Safe Mode as explained in that article. For a first try, simply click the "Continue in Safe Mode" button and see if Firefox starts. If this brings Firefox back to life, it's probably an extension, a theme (or a combination) causing the crashes. Close Firefox and restart it in Safe Mode, and this time mark "Disable all add-ons" and click button "Make Changes and Restart". This will deactivate all add-ons (extensions, themes and plugins), and restart Firefox in normal mode. If it starts, you can begin enabling your add-ons one by one to find the cause of the crashes. When you find the guilty add-on, you can again start Firefox Safe Mode and disable all add-ons, then start Firefox in normal mode, uninstall the sinner and re-enable all your other add-ons. Please post back here with information about the problematic add-on (and any and all details you can find about it), so this can be investigated further. Let me know how above works out, and if I can be of further assistance. Detailed feedback is appreciated and helps us to help more users with similar problems.