if you have fixed the m/b inside a case then remove the m/b from the case and try it outside the case. this is to rule out any shorts due to case.
and guys as he said he is not using the case front panel switches but the switches on the m/b.

if trying the m/b outside the case does not help then it is definitely psu issue.

ps: observe carefully whether the psu fan and the cpu fan does not start at all or it starts for a second or there is a very small movement of the fan blades i.e. attempting to start and then stops.

if the fans start and stop immediately then the psu is shutting down due to over voltage / over current protection.

if the fans do not start at all, not even a jerk, then the PWM IC inside the psu is defective.

Try with a different psu preferably non vip ones.