My Firefox is fine, it works normally (except for Youtube pages which take over a minute to start playing). Today, while FF was open and working fine, I clicked on an url shortcut on my desktop and got the "firefox is already running but is not responding" error - this came after I disabled Microsoft automatic sign-in to apps and services (I run a local account). So I think that's what has screwed things up. So now FF will only open a shortcut if it's already closed, but not if it's already open like normal. If I drag and drop the same short cut onto FF it opens no problem, so I think it's a windows screw up,.. But how to fix it ?