Hi, this may sound stupid but yesterday a friend called me to fix a computer and install Linux

- so i quickly:
it succesfully just halted but didn't turn off. after i came home the computer turned on but just the lights and the fan. nothing was booting, not even the bios! i checked for every cable that could possibly be disconnected but no luck... does anyone know if i messed my computer? if i did... how can i fix my computer

-- i never had this problem before.