Is my HP Probook 4510s over heating?

Hey, i have three problems with my HP ProBook 4510s.

1) After periods of time with extensive gaming use of my laptop, it randomly shuts down in an instant without warning. I was wondering if this is due to over heating? i looked up google stuff to see if i could find a way to open this laptop to check if there is extensive amount of dust inside, but i fail to be able to find a way in. Also just after it shuts down, the base is extremely hot.

2) If my screens brightness is set to around 50% or higher, the laptops back light turns off. everything is still running because i can only just see it in some lights, but otherwise i cant see anything.

3) If the battery is not at 100% and i go to play a game, the same as problem 1 occurs with the instant-no-warning shutting down. This problem does not occur at 100% battery or when no battery is connected.

Other this i have noticed:

About twice the laptop basically coughed... yea, dust came out in splutters, it was relay weird and made me jump. LOL.

Problem 2 can be fixed if i connect an external monitor to my laptop.

I find it pointless using my external laptop fan when the air goes up, seeing that the laptops vents are on the side.

Thanks in advance! :)

Elliot