No mouse, no keyboard, no monitor,,no hope??

Hello, my problem is that my computer turn on but there's no video signal, neither mouse nor keyboard work,,,, all case fans are working including the CPU . I tried unplugging everything, taking out all the ram memory and putting in back one by one turning on the computer every time (32 gigs),,I tried the trick of unplugging the computer and trying to turn it on pushing the power button for 30 second and plug it in again and turn it on,,, nothing,,
In other forum I red that I have to try to boot it from a DVD with an ISO Linux,,, unplugging the disc C,,,,nothing,,,the DVD player works but nothing else,,,I tried changing the CMOS battery by a brand new one,,,nothing. One thing that I notice,,, every time I push the power button on the computer turn on but after a second it turns off for a second then it turns on again and this time it works,,but no monitor, no mouse no keyboard,,,,I'm suspecting the MoBo has serious problems,,,,

Some suggestions??