Dead Macbook Pro?

[Scarlett]

I don't use my Macbook Pro very often, usually only for ease of marking exam papers whilst on my back (can't sit for very long). I switched it on and it made a loud hissing sound. I re-set the date. Then I re-started to see if the hiss went. It didn't. Then I switched it off to try and restart it so I could press ALT and switch to the Windows side. Again it hissed for a few seconds, then went off. Now each time I try and switch it on, it shorts out after a couple of seconds of hissing.
Is it dead, or can this be fixed? It is an old machine, bought in 2011.

[woofgang]

It might be worth getting help from Mac....they have an online chat service.