Acer Travelmate 7520 shutting down.

I have an Acer Travelmate 7520 that sometimes shuts down for no apparent reason.

I suspect it's a hardware fault. Have any of you guys experienced this and what may the cause be please?

Thanks

Does it shut completely down or does it do a restart?

It just shuts down.

It will restart after a short while. I think it's a heat related issue but I want to keep an open mind.

Are the air ports clean of dust? Check them, if not clear use a can of compressed air and blow it out.

Where is the laptop setting when in use?