probably some internal issue that deserves some tech expert's hands.
I am using Toshiba Satellite P855 for past 5 years.
costed me 700US $ running on Windows 8.1
no complains to date.
My system hasn't seen any hardware expert so far.
Except that I have had to change my battery once. well thats obvious for a 5year old system.
I don't have the urge to replace it (even now).