Gazelle Professional shuts down itself once in a couple of days

I've got my Gazelle Professional laptop about a week ago.

It works fine except since I bought it turned off itself unexpectedly two times. Both times I was at the computer and was pressing keys in the right bottom part of the keyboard (maybe this is relevant?), like "->" and Ins. The temperature of the system is low enough. How can I diagnose the reason of such behavior?

I will probably have to return the computer because I need to be sure in it and don't be afraid that it will turn off in the middle of file editing.