Seems like this issue recurs every now and again. Right Click on a link and try to "Save Link As..." and Firefox hangs. All of my browsers started doing it in the last few weeks. Suspected PC Matic, as I had installed it recently, but disabling it did not help. Clear Cache and Default Settings seemed to once or twice but then problem persisted. Looks like it's a bug in the pop-up blocker. Disabled it and "Save Link As..." again works perfectly. Same for all other browsers. Looks like pop-up block does not recognize "Save Link As..." as a permitted pop-up and the system call to File Explorer (Windows 8.1) has nowhere to go. Task freezes solid and can only be killed by Task Manager. HTH find the real solution. Thanks!