Monitor not recognised after sleep

[Philcog]

Has anyone any ideas please, after starting up after standby, my monitor has no input signal this happens about once in every three times. Because there's no screen, I have to force quit!

Phil

 

[townsbg]

There is probably some kind of hot key combination that will activate it.

 

[Philcog]

I think there's more to it than that as there's no input to it, maybe a graphics card problem? I can't find a keyboard shortcut anyway to turn a monitor on, in fact the monitor is on anyway when this happens.