Dell Latitude-e5550 (Broadwell) - keyboard problem

HI, everybody!

I bought three laptops same types (Dell Latitude e5550, i5-4310U, Intel HD Graphics 4400, 1920x1080, RAM 8GB, 500GB ) from two different shops and they had the same problems with the keyboard. I returned successfully all of the laptops and I bought another (fourth) from the first shop whose version is newer(Dell Latitude e5550, i5-5300U, HD Graphics 5500,1920x1080, RAM 8GB,  500GB Broadwell) then others. But it has the same problem.

Keyboard problems :

   1) when I typed a button(no matter which button was typed), and I released the button, the symbol appears multiple on the screen.

   2) sometime, when I typed certain letter - for example 'c', successfully (no multiple) and after that I put my hand somewhere on the laptop frame, but not on the keyboard, I had the previous problem - multiple typing appears again(the last typed symbol).

I also want to ask about the working temperature and the battery life.

The laptop(Broadwell) working temperature is between 50 - 60 degrees Celsius (and above sometimes) when I am not starting applications or running only one "weight" program.The previous laptops never exceed 45 degrees Celsius or they were exceeding that temperature very rarely(when I am using more applications).

I tested battery life today and the laptop worked at about three and a half hours.

It worked with 60% of brightness and it was idle during the most part of the working time.

I used LibreOffice Writer and some web browsing, but I didn't watch any clips.

The laptop comes with brand new loaded OS Ubuntu 14.04.01 LTS.

I installed the newest version of  Ubuntu, 14.04.02 LTS but the problem with keyboard still existing.

Please, if somebody can help, to reply to me. Thanks !

Regards