problem: monitor switching itself off

Hello everyone, I have some serious problem with my lcd panel or graphic card (still not sure). so the thing is it turns itself off for like 5 seconds and then back on and everything is fine till next time it happens... lcd is a samsung 192n and graphic card is a palit geforce 5200, the thing is that the card doesnt have a fan - just a radiator (it came like this stock). so what you guys think is more probable - lcd damage or graphic card overheating?

and one more thing about the lcd - there appeared some small grey dot on it. its like 2x2 pixels (no, its not a dead pixel) and its grey, NOT black, not red or any other subpixel color but grey. looks like the screen is dirty but its not cleanable. what can it be? could it possibly be fixed?

if anyone could help me, I would really appreciate it

btw. that was my first post so please no flaming if I did something wrong