So you are getting a random name website page claiming to have a so called urgent update for Firefox and a prompt to download a fake firefox-patch.js file?. The random name of the website alone should raise a flag that it was not legit. '''This is not from Mozilla or the Firefox web browser'''. The fake firefox-patch.exe and firefox-patch.js files can install things like trojans, viruses, unwanted software or to download additional stuff onto Windows based on past reports if the user runs them. The Firefox updates are done internally in Firefox (with a .mar type of file) whether on Windows, Mac OSX or Linux (since Firefox 1.5 almost eleven years ago) or by download from mozilla.org like say www.mozilla.org/firefox/all/ You could try using a adblocker extension like uBlock Origin to block theses fake ads if you keep getting them. https://addons.mozilla.org/firefox/addon/ublock-origin/ Unfortunately this has gone on for a while now with one or two new sites reported almost everyday. https://support.mozilla.org/en-US/forums/contributors/712056/