New Dell Monitor turns on,stays like it for ~ 5 minutes then turns off,after it turns on again and after 1-2 seconds it turns off again and it does this repeatedly
You should simply return it (RMA). There's little point in trying to troubleshoot something like that. Specially if the screen stays black. When it's on, can you use the menu for the monitor? If so, there may be a reset option. Try that before RMA'ing it.