Okay reading between the lines and I shouldn't but it feels to me as if you have had this camera for a while and are familiar with its functions would I be correct in assuming this? Did you download the pictures from your assignment using your camera and a USB cable or did you use a card reader?
Have you another memory card you can put in the camera?
What I'm hinting or leading up to is there any chance you disconnected either the USB cable or pulled the memory card out before shutting it off as in eject or safely remove?
Will the camera allow you to move into the set up or command functions? I know you said nothing else works but it shut off and didn't come back on I'm hoping you messed up on removing the memory card from the reader OR the internal battery has just dies and taken all the clock functions and your setting with it.
I don't know if you have a manual so here is a link to a PDF manual
Sorry it's a biggy you'll need to copy past it but I'm using the manual now tracking down the internal battery so it is a good link
Page 42 of this manual there is a "Disp" button here is a screen shot did you maybe touch this and shut the screen off?
If you can access the command functions page 114 has the camera reverting to default setting sequence.
On page 115 you can actually shut off the monitor display, why anyone would want that I'm not sure at this point. I'm just throwing out possibilities.
I've given you some things to look into see what happens.