if it hasn't fully downloaded yet, best thing you can do, is disconnect yourself from the internet, hit Ctrl+Alt+Del, go into the processes tab, close Iexporer.exe(if you are using Internet explorer), Firefox.exe(If you are using firefox), Chrome.exe( if you are using chrome) etc. after you have done this, clear your cache, and cookies, reconnect to the internet, re open your browsers, and continue surfing the net like usual.
