I'm using Firefox Quantum 63.0.1 64-bit on a Win 7 Home Premium desktop computer. There are some web sites I use that use Flash and they will work fine on a given page, but the computer hangs when I switch to another page. My work-around has been to always keep 2 tabs open. When the computer hangs, I use Windows Task Manager, hit "End Task", and then when there's a pop-up up that says "Firefox is waiting for a response from you" I hit "cancel" and then hit "cancel" again when the pop-up says "Are you sure you want to close 2 tabs?". At that point the web site that was hanging things immediately finishes loading and everything is fine until I switch pages again. I'm not 100% sure that this has to do with Flash. I thought it did, but then today the same thing happened on a site where I was changing credit card information, and I'm not sure why it would be using Flash. Also, whenever I get up to do something else, I use Options to clear the cache, then I close Firefox. I also use Manage Cookies to clean out the cookies about every 3-4 days. In addition to Shockwave Flash, the other add-ons I have are OpenH264 Video Codec and Widevine Content Decryption Module (which seems to have been installed by Google - not sure if I need it). In addition, I clear the Flash cache at least once a day. I have preferred using Firefox for a long time, and would hate to have to change to another browser, but this is getting annoying and cumbersome. Any help would be appreciated!