Samsung S Advance: won't turn on or screen defect?

Dear people,
My phone seems to be unable to turn on. When I press the power button, most of the time there is no respons; sometimes it gives a short buzz and the menu and back buttons light up. The same happens sometimes when I plug in the power cable or when I try to go into Recovery Mode.
Weird thing is: the alarm clocks still go off. So I thought it might just be that the screen is broken.

I tried multiple power cables and power outlets. The phone is not recognised by my laptop.

I don't give a damn about this damn phone, but I would hate to lose all my photo's and appointments..

Who has an idea?
Thanks,
Robert