Help with Laptop Graphics/display

Hello all,

I am having trouble with my laptop. It is a Gateway Series NV53 and roughly three years old. The monitor randomly started bugging out and going psychadelic on me. Being in BIOS or Windows has no effect, I also tried an external monitor via HDMI and VGA, none of which send a signal to the external monitor (yes, I tried Windows Button+P). I thought it may have been a dodgy connection which is also not the case after dismantling the laptop.

Roughly 1 year ago during spring cleaning, I applied thermal paste between the heatsink and onboard chipset to alleiviate cooling problems. I have NEVER had a problem with the chipset or CPU heat thus far.

At this point, I have done all I can as far as troubleshooting goes. Any other help is greatly appreciated.