Black screen: Need Help

[D_J]

I have a Compaq desktop and I can't even get to the log in. I can pull up the bios that is it. I had reset everything back to default then saved changes and I had finally made it to the log in page, but to my angry surprise the mouse nor the keyboard worked. I then restart the PC and now I am back to where I originally started black screen with the flashing line. I could use some help I just hope I asked in the right place!

 

[printerhead]

It looks like your OS does not work or it is missing. On my Compaq to reset you press ESC then f11 if you tell me your exact product number I can work it out exactly.