My Mac mini display goes black when it should be on login screen. Works to display the apple and progress bar on startup.

I am using a hdtv for display and it just started with this issue. When it powers up the apple with a progress bar is on screen, then goes to sleep. When I move the mouse the computer wakes but only the cursor appears on a black screen. I have tried unplugging the power cord and holding the on button as I put it back in. This caused the fan to run continuously. After a couple of tries I got the fan to stop but the display issue is still happening.