hello, please uninstall or upgrade avg: https://support.avg.com/SupportArticleView?l=en&urlName=How-to-upgrade-AVG-8-5-9-0-2011-or-2012-to-the-latest-version

and afterwards download and try to install firefox again from: https://www.mozilla.org/en-US/firefox/all/

Note that you need to reinstall Firefox if there have been problems with updating because some files were locked by other (security) software. You can't use a file that you found elsewhere.

I tried to uninstall AVG thru control panel it won't uninstall Avg won't open win defender says AVG is not on , I can't close defender or turn on AVG don't know whatto do need more help thank you

Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen or hold down the Shift key) to see if that helps.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
• http://www.7tutorials.com/4-ways-boot-safe-mode-windows-10

AVG website had an uninstaller , that worked,so uninstalled firefox an reinstalled everything seems to be working again , thank you phillipp and cor-el you rock