Acer Aspire laptop won't turn on

I know this has been posted a lot but mine seems to be a little odder than what has been posted. My laptop just shut off one day and will only turn on when the back/bottom of the laptop is not on, which means my motherboard is completely exposed, once I put the back/bottom back on it will not turn on. I thought it might have been the fan, its not brand new fan and still wont turn on. Any help would be awesome!

This is not an easy one to help with without have the laptop in my own hands. You will most likely find that there is a bad connection somewhere that is being broken when the base is fitted. Have a good look at all the ribbon cable connections as one has probably worked loose.