I do not like trouble shooting stuff that should have been done right the first time so : Please uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files and C:\Program Files(x86) Then restart system. Then run Windows Disk Cleanup. Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved. Reinstall with Current Release Firefox 57.0 with a Full Version Installer https://www.mozilla.org/firefox/all/ Please remove Shockwave Flash 24.0 r0 it is a major security threat. Please use this to do since is so old : https://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html Flash Player Version: 27.0.0.187 Current Version, yesterday. https://get.adobe.com/flashplayer/otherversions/ Step 1: Select Operating System Step 2: Select A Version (Firefox, Win IE . . . .) Note: Other software is offered in the download. <Windows Only> Please let us know if this solved your issue or if need further assistance.