Monitor completely grainy

[MEL1315]

Hi guys,
My desktop monitor has been giving trouble lately. About working for an hour, it turns completely grainy and all i can do is to switch off power. The interval of this occurrence decreases every time i reboot it. Can someone check the image and please help me out...

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It is not stable like in the image, but in varying colours.

 

[Petrossa]

There are 2 likely suspects here.
1. The monitor itself. You can try hooking the screen up to another pc and seeing if it does the same thing. If it does, then you need a repair. If not, then
2. The graphics card itself, whether you are using onboard (in which case a new motherboard might be required) or a graphics card (again, try testing in another pc with a different monitor to see what happens). If the problem re-occurs, then you need a replacement.