Yesterday I upgraded my laptop from Windows 7 to Windows 10 and at the time of installation it gives message it may restart several times. It progressed to auto restarting after the installing step, but after the restart and gone through the dell startup screen blank, there is no cursor or anything on the screen, and itís just black. I left it for over half an hour and still nothing. I did a shut down pressing the power button. Again I stared my laptop and it works but my bitdefender antivirus has been stopped working. So I uninstalled and searched for the windows 10 compatible bitdefender patch and installed.

Now its working perfectly.