Faulty GPU or CPU? (overheating?)

[Vulmex]

My GPU has recently been freezing that is when I am doing something graphics intensive the screen will freeze and the whole screen will have parallel lines strung across it while the screen is "bleeding" these white lines prohibit any activity on my computer (no interaction at all) and I was wondering how I could fix this. The only way to get my computer back is to manually shut it off and when I turn it right back on it tries to boot then shuts off immediatly right before the boot loader.
It seems to me like something is overheating, but I have sucked the dust out of my computer multiple times and that usually fixes any over heating problems or has in the past (lack of compressed air)
Can someone please help me troubleshoot this issue I would just put in a new GPU but its like built into the computer...thanks in advance guys

p.s. I have a HP Pavilion dv7 laptop with a ATI Mobility Radeon HD 4650 Series (with the display drivers updated)

 

[patonb]

You need to run a temp monitor program to find out what the temp it's getting.

Use something like gpuz to monitor it.

 

[Peter.Cort]

if it is overheating the only thing you can do is make sure that the fan's are blowing 100% and if that doesn't fix it get a cooling pad for it, preferably one with a fan. Other than that you can't really do much aside from putting new thermal paste on the heatsink.