I need help! :) Disclaimer: I'm actually trying to help a friend of mine, and I personally spent over an hour at my friend's apartment trying to fix his Firefox. I'm posting here so I can hopefully get some more tips from all experts here. Symptom: Firefox completely hangs when playing back Flash videos (eg. Youtube). You can usually still hear the audio in the background, but the video freezes, and indeed the entire UI freezes. You can't even click the red [X] button to close the window at that point. Workaround: Getting the Windows Task Manager up and killing plugincontainer.exe makes Firefox respond again, showing the "Plugin crashed" box in place of the video, and you can finally interact with the browser again. I've tried the following: * Ensuring that he's running the latest Firefox (8.0.1) * Upgrading Flash to latest version - same problem before and after * Upgraded the graphics card drivers to the latest version (it's a ATI Radeon HD 3200) - same problem before and after * Created a new Firefox profile - still the same problem * Made a clean install of Firefox by wiping the program folder - still the same problem * Created a new Windows login account - still the same problem * Tried in IE - it works fine! * Tried in Chrome - it works fine! I'm suspecting that this is some sort of graphics driver/flash issue, but what really boggles my mind is that it works fine in Chrome, which (I think?) uses the same non-ActiveX version of the Flash plugin. Another piece of evidence that I think points to the device driver: running Windows in Safe Mode actually makes the video play fine (although very very low fps). Any clues, anyone? I feel like I've tried all possible troubleshooting steps!