Acer Aspire 5742 shutting down unexpectedly with Windows 8.1

Phatossi

 Hello there, I recently formated my laptop that I bought with Windows 7 preloaded, and installed Windows 8.1, but I am having problems with it.

 

While I open a few applications simmultenously, it over-heats and it unexpectedly shuts down. 

I cannot even do a Skype Audio or Video Call at all, because it shuts down, even though, no other programs are running.

 

I saw at this video on YouTube 

https://www.youtube.com/watch?v=wEXkEmSn92k

 

that I should install that Acer'ssoftware that manages the power of the CPU, but I wasn't sure, so I decided to ask you here. Could you please help me out solve this problem?

 

Thank you very much.