Can you try creating a new Firefox profile? In addition to bypassing most current add-ons and custom settings, it should have completely fresh settings databases and a fresh cache folder.

Close Firefox and start up in the Profile Manager as described in Profile Manager - Create, remove or switch Firefox profiles. Any time you want to switch profiles, close Firefox and return to this dialog.

If the new profile is free of crashes, you can migrate key settings like bookmarks from your problem profile to the new one. See Recovering important data from an old profile.

Any luck?

I forgot to ask: what program did you use for the troubleshoot? Is it a built-in feature of Windows 7 or something from your computer's manufacturer or a third party program?

Did this start after another software update, e.g., Windows update?

The problem began because my computer had to be sent in because it wouldnt turn on so i had to get it fixed they replaced the motherboard this was the second time the motherboard was replaced and once they did that my firefox hasnt worked the same. I can go on google chrome but thats not what i prefer to use.

& when i right click on firefox it says troubleshoot so im assuming its built in to my computer. im not sure.

I tried the profile manager to create a new profile and that has seemed to work so far. No crashing but it does freeze when i got to facebook and then i have to click ctr alt delete to open task manager to end firefox. It happened twice, the third time i went to google, then twitter and it didnt freeze. I then went to youtube and it froze. So Facebook and youtube make it freeze. Any idea why it does that?

& thank you so much for helping and responding to me.

Also i forgot to add that since i did that profile manager and changed my firefox profile when i click to open firefox my computer will say user account control. "do you want the following program to make changes to your computer and it says Program name: Firefox verified publisher: Mozilla firefox. file origin: hard drive on this computer"

Each time i click to open firefox i click yes and thats when it works. but freezes on certain websites.

Regarding the UAC prompt, I wonder whether Firefox is set to "run as administrator"? You could check this and turn if off by right-clicking the Firefox icon, choosing Properties, then the Compatibility tab.

Facebook and Youtube are both complex sites. One thing to check is Flash. You might try disabling the new protected mode in Flash 11.3, since that feature is currently being debugged. See this support article from Adobe under the heading "Last Resort": Adobe Forums: How do I troubleshoot Flash Player's protected mode for Firefox?

No firefox is not set to run in administrator.

I tried the last resort thing in the adobe forums. Facebook works when i have all my plugins disabled. But i feel like its only the adobe flash that makes it freeze. (Adobe Flash Player 11.3.300.271) but the plugin for firefox i think is called "shockwave flash 11.3.300.271) so when i have that disabled facebook works just fine, youtube doesnt work because it needs flash to watch videos and when i enable it, it makes firefox freeze.

Also when i open firefox i still get that same message " user account control. "do you want the following program to make changes to your computer and it says Program name: Firefox verified publisher: Mozilla firefox. file origin: hard drive on this computer"