No bootable device then now I can't open because shutdown

Hello,
Asking for a help asap with my Acer PC ,, I can't open it ,,before there a message in screen ,no bootable device-- please restart system then I can't restart because its not working, then I just wait until now I try to look again my PC then no no battery I try to charge I think it's charging but still I can't open it can somebody help me


Thank you