Some programs and video files dont work.

Question

Some programs and video files dont work, get a crash report everytime I close, even after an uninstall everything and re install.
So I try playing some videos and it gives me an error, which I can watch on Chrome. Soundcloud doesnt seem to work, again works on chrome, and before I could watch WebM's but now it says not supported MME. Also everytime I close I get a crash reporter. I tried uninstalling and reinstalling but nothing seems to work. I just happened recently. Also cant play soundcloud. Tried everything, feeling like going to chrome where things work and support is actual support

Answer 1

Protected mode works on some systems and not others. Since two of your four crash reports were related to Flash, I thought it was worth a try, but it's up to you whether you want to try it.
I'm not sure whether the issue with WebM video is a setting issue or a program files issue or a system issue.
'''Create a new Firefox profile'''
A new profile will have your system-installed plugins (e.g., Flash) and extensions (e.g., security suite toolbars), but no themes, other extensions, or other customizations. It also should have completely fresh settings databases and a fresh cache folder.
Exit Firefox and start up in the Profile Manager using Start > search box (or Run):
firefox.exe -P
Don't delete anything here. Any time you want to switch profiles, exit Firefox and return to this dialog.
Click the Create Profile button, choose a name like TESTING, and skip the option to change the folder location. Then start Firefox in the new profile you created.
Any better results with WebM video or shutdown?
When returning to the Profile Manager, you might be tempted to use the Delete Profile button. But... it's a bit too easy to accidentally delete your "real" profile, so I recommend resisting the temptation. If you do want to clean up later, I suggest making a backup of all your profiles first in case something were to go wrong.
'''Clean Reinstall'''
A regular reinstall may leave some stray files in your programs folder. This method is a bit cleaner.
(1) If needed, download a fresh installer for Firefox 30 from https://www.mozilla.org/firefox/all/ to a convenient location. (Scroll down to your preferred language.)
(2) Exit out of Firefox.
(3) Rename the folder
C:\Program Files (x86)\Mozilla Firefox
to
C:\Program Files (x86)\OldFirefox
(4) Run the installer you downloaded in #1. It should automatically connect to your existing settings.
Does Firefox behave more normally?
Note: Some plugins may exist only in that OldFirefox folder. If something essential is missing, look in these folders:
* C:\Program Files (x86)\OldFirefox\Plugins
* C:\Program Files (x86)\OldFirefox\browser\plugins