Is this for all sites? Can you copy and paste text from this web site? (I was just able to) It is possible that the site in question disabled that function. Can you right click on that site to get a Copy function? (right click can also be disabled on a per-site basis) If this is site specific - go to Firefox/Edit/Tools -> Preferences/Options -> Content tab and then uncheck "Enable Java Script." (known as JS for short) Reload the site in question. If it works, then that was your culprit. If not, then you have another problem. (perhaps the key bindings for your OS have been altered) If you don't want to turn JS off all the time for all sites (you will lose functionality on many sites and some will not display correctly with it off) then install the NoScript add-on which allows you to white/black list sites and their JavaScript permissions. (you can "always allow" for those sites you trust, and "temporarily allow" for sites you rarely or occasionally visit) Do note that many times, scripts are nested. (meaning one script will load another, then that one, another, etc.) This can get annoying, but I find it a small trade off to have full functionality AND security from malicious scripts.