My monitor randomly turns on and off, the actual screen goes blank but the moniter still has power

The cable seems ok but I don't have a spare to see if that's the problem so is there something else that could be happening?

Don't really want to shell out for a new moniter if it's the computer that's gone wrong but what can I do to eliminate the suspects when I don't actually have a moniter to view?

Thanks

Can I also make the modest request that the mods to keep it here for today rather than move it immidiatly to the it room, thank you