hp dv6636nr problems. Please help.

Hey guys I have 2 ongoing issues with this laptop, and I was wondering if someone could help me with any suggestions or solutions.
My first problem deals with the display. After 10/20 mins of use the screen become jumbled. Usually when I'm scrolling.
For example:
if my screen were to look like this:

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after the problem happens my screen will look like this
- - - -
- - - -
- - - -
- - -
I've tried different drivers but the issue still happends.
My second issue is that the laptop continually freezes. I've closed several processes, but have not been able to fix this issue. Usually, everything but the mouse freezes first, and then my mouse, and then I have to hard boot to get out.
If there are any solutions to this please let me know. Thanks.

 

It sounds like an overheating issue, either with the CPU or GPU.
Can you tell if the fan inside it is working/clean?

 

Hmm, from what I can tell it seems to work. I feel the heat and all coming out from where the fan is. Is there anyway else to check?