Your crash report seems to indicate this relates to javascript use, so I would suggest that you try to create and use a new clean profile, and set it to start on the default homepage or a blank tab, rather than restoring a previous session, or any site that could cause problems. If you can at least get Firefox to start without crashing within seconds that will be some progress. * see [[basic troubleshooting#w_8-make-a-new-profile]]_8-make-a-new-profile ---------- Report for your CrashID [https://crash-stats.mozilla.com/report/index/5e0f5763-e851-4a83-a7ec-761262120509 5e0f5763-e851-4a83-a7ec-761262120509] * Crash Signature: js::mjit::EnterMethodJIT(JSContext*, js::StackFrame*, void*, JS::Value*, bool) * related bugs include ** ''Bug 716900 - Crash on Javascript heavy site '' <br/> But that specific bug does not apear to be affecting Firefox 12, and was fixed in some versions ** Bug 595351 - (SadJägerMonkey) [meta] (Enter)MethodJIT crashes <br/>But that is only an old tracking bug, listing related bugs