Acer 5737z random shutdown

Hi,
Only new here and after some advice, I have an acer 5737z that shuts down whenever it wants. I have changed the ram with good ram known to work, changed the thermal paste to arctic silver 5,even though it does not feel hot, cleaned all fans etc, swapped out a mobo with my good one that works and changed hard drives and this thing still shuts down randomly. So any advice wold be great.
thanks in advance.

 

Did you check the PSU or test with another one?

 

Thanks for the reply, yes I have tried swapping the power supplies. Sometimes it will boot and load normally and work for a while then freeze, then the random shut downs start.

 

Does this happen both with and without the battery?

 

Hi, yeah it does, does not matter if on ac or battery

 

There's not much left to test
It can be either a short circuit caused by the screen, DVD-drive or touchpad/keyboard.
Only the former seems remotely likely- can you disconnect internal LCD and test with an external screen for a while?

I assume you have no USB devices connected or anything like that?

 

Thanks again, I disconnected the dvd and keyboard, no usb devices, so the last thing I could think of was the screen, i will give it a try, thanks for your assistance.