Laptop auto shutdown

hi guys, first post here and here's the problem.

I got a laptop which is basically two months old. And yesterday while I was having a meeting, the laptop shut itself down automatically after about 15 minutes. Then I head to library and switch it on, it works perfectly fine for about an hour until it shuts down again. Both cases happened under air-conditioned environment.

I sent it to the computer shop to have it checked and they told me that they switched it on for the whole day without experiencing any auto shut down.

And today, I brought it back and was using it for about two hours then the screen flickered one time.

GPU temperature was about 35 degree celcius. Then it raised up to 55-65 in about three hours.

May I know what's the problem I'm experiencing here?

It sounds like the video card either has a defect or has a problem with cooling. If you look through the system logs it may give a hint if that is what causes all the shutdowns.

If you download NirLauncher it has several log viewers including event logs. Easiest way to find stuff is click on All Utilities and do a Control f search for "crash."

It is free and handy to have in any case.

Edit: also this may be helpful:
What information appears in event logs? (Event Viewer) - Windows Help