Update from Firefox 3.6.17 to 4 - Browser window will no longer open (can see running in processes), safe mode wont open to troubleshoot,re-installed 3.6.17 all ok again (running Windows 7 pro 64bit)
I did try getting the safe mode to run from Win7 prompt, Firefox can again be seen running in processes, window wont open. Tried another browser no problems. Tried other troubleshoot solving from FAQ, no luck. I also found that while Firefox was showing in the processes my other browser would not run/open window? until i restarted my computer. Finally i uninstalled Firefox 4 and re-insatlled 3.6.17 everything worked fine again. Running Windows 7 Pro 64Bit, system up to date on all updates.