Windows 7 - Green Pixels, Screen Freezes, Random Turn Offs?

Hi
I have been getting these green pixels appear on my screen, sometimes they are pink depending on the background.

The computer also freezes alot and i cannot do anything not even move the mouse. When the green pixels start coming on i usually turn off the computer. but i decided to leave it on to see what happened and the longer i left the computer on for the worse the pixels got. eventually the bottom half of the screen freezes and i can only use the top half, then the top half will freeze. when this gets to its worst stage i have to leave the computer for 2-3 days before i can use it again or else they are still there? I Think this must have something to do with my graphics card.

Graphics Card: ATI Radeon HD4600 Series

Please i really need help on this one.

Did you go to device manager and look for any yellow warnings?
Did you update the graphics driver?

Yeah it says it's fine in device manager and i have updated the drivers :/

Type event viewer in search; look for any critical errors, that may give some information.

I get a critical error: Kernal Power

um guys a quick question.how do i post threads on sevenforums. i am new to the site

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... If it was a driver issue i don't think the actual green pixels would be showing up in the screen shot provided would they?? It seems more like a software conflict... does it still do it if you move your mouse over the spots?

The ones i move my mouse over flicker a bit then come back when i move my mouse?

Actually i dont think the kernal power is the problem. all that is is when i simply turn the computer off on the plug because there is no other option.
Help Please