RE: Computer has black screen after downloading windows 10
Which Dell computer did you have? Did you verify your computer can be upgraded to Windows 10 prior to upgrading? You have to be able to get into Windows 10 in order to to turn off Sticky Keys/Filter Keys. Once you are logged into Windows 10 you would click the start button and choose settings. From there choose Ease of Access-Keyboard. In this section you will see to turn off various options including Sticky Keys.
Below is a link that provides information for resovling the black screen issue. If it calls for entering Safe Mode on your computer you would start the computer and TAP the F8 key,.