Some people at Go Firefox! have reported some issues when attempting to upgrade from Firefox 3.6.16 to Firefox 4 on Windows. A couple I have seen include: Error 0x00000004 in firefox.exe Reboot required to complete update. User get this message when attempting to launch or uninstall Firefox via Windows Control Panel. In both cases firefox.exe or one of it components got corrupted during the update. To fix this issue follow these steps to manually remove the damaged Firefox and to install fresh: Got to getfirefox.com and download (do not run) Firefox 4 Close Firefox Locate your Firefox install folder. Default…