Firefox freezes when Flash is loaded
Using Firefox 25, Windows 7 SP1, Flash Version: 11.9.900.117, NVIDIA Driver R331.65
Flash causes Firefox to become unresponsive and 0% CPU used by Firefox or Flash. If Flash is disabled, and all open Flash instances killed, Firefox resumes normal operations. Persists with a brand new profile, and in fact, even after reinstalling entire operating system. Chrome un-impacted, but Nvidia drivers crash so often they're mentioned by name.
Opaite Mbohovái (3)
If you haven't already, disable the Flash Player plugin's protected mode feature. See this support article from Adobe under the heading "Last Resort": Adobe Forums: How do I troubleshoot Flash Player's protected mode for Firefox?
Other standard recommendations for Flash problems include:
(1) If you have any recorders/downloaders that interact with Flash media make sure they are as up-to-date as possible, or disable them temporarily.
(2) Disable hardware graphics acceleration in Firefox and in Flash
(A) In Firefox, un-check the box here and restart:
orange Firefox button (or Tools menu) > Options > Advanced > General > "Use hardware acceleration when available"
(B) In Flash, see this support article from Adobe: http://helpx.adobe.com/flash-player/kb/video-playback-issues.html#main_Solve_video_playback_issues
Please note that Chrome, Firefox, and IE each use different Flash player components. Confusing!
Disabled protected mode. Not using any recorders. Disabled in Firefox, but can't do so in Flash, because it immediately causes the program to lock up.
Nvidia 560M