Mozilla Firefox Error Couldn't load XPCOM

When you open Firefox you get this Error: “Couldn’t load XPCOM.” 1. Backup your firefox profile (settings, bookmarks, etc) by copying the Mozilla folder in “C:\Users\[UserProfileName]\AppData\Roaming\” to your desktop. 2. Now Uninstall “Mozilla Firefox…” and “Mozilla Maintenance Service” from “Program and Features” in the Control Panel. 3. Next delete the Mozilla folder from “C:\Users\[UserProfileName]\AppData\Roaming\” 4. Now Download and install Firefox using another browser. (If you click System & Languages then find your language this will be the offline installer) 5. As you see none of your settings or bookmarks are saved. This is a fresh install. Now Close Firefox. 6. Next delete the contents of the Firefox folder from “C:\Users\[UserProfileName]\AppData\Roaming\Mozilla\Firefox” 7. Now open backup you saved to the desktop and copy the contents of the firefox folder back to “C:\Users\[UserProfileName]\AppData\Roaming\Mozilla\Firefox” 8. Open Firefox. Your Bookmarks and settings are back!