- Any lights coming up on your motherboard? any fans spinning? does your keyboard lights up (num lock or caps lock led)
I would boot with minimal hardware: no hard drive or cdroms or card reader, with only one memory stick at the furthest memory slot from CPU ( re-seat it), reseat GPU carefully in it's PCIe slot, double check CPU 4-8 pin power connector on the motherboard, and GPU has correct PCIe power connector attached from PSU, verify all PSU cables both ends are attached correctly, motherboard power connector ( re-plug), verify CPU cooler fan is connected to motherboard dedicated CPU_FAN header, and if possible power on motherboard by shorting power pins on front panel motherboard header (not use case power button= disconnect all case front panel wiring), or best have motherboard sitting outside the case on an isolating surface like a cardboard).