My monitor flashes up contrast on and off and sometimes luminance as well. I have to press the button front of screen to remove it but as soon as I let it go it comes back again. It's driving me mad please help!

Hi Pat and welcome.

Sadly, you gave us nothing to go on but one symptom. We know nothing of your computer, the monitor, the graphics card, the operating system, how long the problem has been going on or anything. At this point, all I can suggest is to make sure your cables are securely fastened.

Hi Pat,

If you needed to press the button at the front panel of your monitor to make the monitor working properly, I would like suggest you check the button connections on your monitor,
seems you have your monitor connection oxizixed or the spring that controlling the button got stucked somewhere so it keep the monitor auto adjusting the contrast itself.

Hope this helps!
Pctestcard