Two things to try:
One, check where the front panel switchs connect to the motherboard. The black connectors from the panel will have a triangle faintly marked on them indicating pin 1. Look on the motherboard or in the motherboard book to find out which side of that pin block is pin one. Make sure all the connectors are on in the correct location and oriented properly- polarity matters.
Two, remove all accessory cards and cables from the motherboard, only that which is needed to boot: power supply, front panel, graphics card. Make sure RAM is firmly and correctly installed. Ditto for processor.
One, check where the front panel switchs connect to the motherboard. The black connectors from the panel will have a triangle faintly marked on them indicating pin 1. Look on the motherboard or in the motherboard book to find out which side of that pin block is pin one. Make sure all the connectors are on in the correct location and oriented properly- polarity matters.
Two, remove all accessory cards and cables from the motherboard, only that which is needed to boot: power supply, front panel, graphics card. Make sure RAM is firmly and correctly installed. Ditto for processor.