A short, might preventing the board from starting. Check the standoffs between case and board and make sure that the case fans are connected to the motherboard only, not to both motherboard and power supply.
'''''Tips:'''''
As long as the power supply did not damage the hard drive control board all the files should be fine. But do remember, [https://www.ilounge.com/articles/why-you-need-minitool-shadowmaker-to-back-up-your-pc|back up] you computer is a good way to prevent loss caused by any unexpected.