Dv6 laptop crashes when playing games

Hello,

my laptop has issues whenever I'm in a game - WoW, CoD, anything that takes any kind of graphical power. I don't even have to do much ingame - just log in, stand around doing nothing at all, and wham - crash.

Three things can happen;
It either gives me a purple screen with vertical stripes (yes, graphics issue right there) - this is the least frequent.
It can also just simply shut down, with a tiny little 'wheep' sound. (Sounds like a heating issue, non?)
Or, the most frequent one; Everything freezes. Screen, sound, mouse, everything. I have to then close down my laptop by pressing the power button untill it stops squirming and wait for 5-10 minutes before turning it back on. If I don't wait, it does the same 'wheep' noise and shuts down for me.

Now, to try and solve heating issues, I have already invested in a can of compressed air that I clean the fan with atleast once a week, while the computer is on to get the best possible circulation - and I have invested in a Logitech N100 cooling pad.

The cooling pad -does- take off 10-20 degrees celcious - depending on whether I have my window open or not. But it works at its best when I am -not- playing a game, but simply just doing study work.

I have tried updating my drivers - there's no available update. They're apparently all up to speed.

And I have tried various things like shutting down all other programs etc. And playing any game on the lowest possible settings. But it continuously does this.

I'm guessing that the only thing to do is bring it to get repaired - but I'd like to ask here if anyone ever has similar issues.