laptop freeze than its shutdown or restarts why?

Netrix

Estimable
Sep 1, 2015
2
0
4,510
Yesterday i attached 2 extarnal hd in laptop and startd to exchanging data

After sometime it display turnd in mix colors than next second it turndoff
And system frozed no sound key nothing was working
Only fan was working.. Than it shutdown it self and than i click on power but and its on..

Now this happening again and again

Laptop is Hp g6 2301ax
4gb ram
Amd a8 apu
7670M g.card
Win 7 ultimate. 64Bit