We have a general article with suggestions on this problem: [[Firefox hangs or is not responding - How to fix]]. A few weeks ago, there were significant problems with Flash and Windows 10, but I don't know whether that is still a problem combination. Since Flash is used pervasively through the web, I suggest the following to minimize potential issues with Flash during your troubleshooting: (1) To avoid unnecessary pain on sites where Flash is not actually essential, try setting Flash to Click-to-Play ("Ask to Activate"). This will delay Flash from starting on a page until you approve it. To set "Ask to Activate", open the Add-ons page using either: * Ctrl+Shift+a * "3-bar" menu button (or Tools menu) > Add-ons In the left column, click Plugins. Look for "Shockwave Flash" and change "Always Activate" to "Ask to Activate". With this setting, when you visit a site that wants to use Flash, you should see a notification icon in the address bar and usually (but not always) one of the following: a link in a dark gray rectangle in the page or an infobar sliding down between the toolbar area and the page. The plugin notification icon in the address bar typically looks like a small, dark gray Lego block. (If it's red, Flash needs updating.) The delay in activating Flash can help distinguish between problems caused on initial page load, styling, and script activation vs. loading/running Flash. If you see a good reason to use Flash, and the site looks trustworthy, you can go ahead and click the notification icon in the address bar to allow Flash. You can trust the site for the time being or permanently. But some pages use Flash only for tracking or playing ads, so if you don't see an immediate need for Flash, feel free to ignore the notification! It will just sit there in case you want to use it later. (2) A common cause of unresponsive script errors on Windows Vista and higher is the protected mode feature of the Flash player plugin. That feature has security benefits, but seems to have serious compatibility issues on some systems. You can disable it using the Add-ons page. Either: * Ctrl+Shift+a * "3-bar" menu button (or Tools menu) > Add-ons In the left column, click Plugins. On the right side, find "Shockwave Flash" and click the More link. Then ''uncheck'' the box for "Enable Adobe Flash protected mode" and try that for a day to see whether it helps.