motherbored light turns but nothing else!!

[ben12144]

Im trying to build my first computer but the only thing that turns on is a green light on the motherboard. i know everything is compatible and i checked all the wires.

 

[Dark Lord of Tech]

Specs?

 

[ben12144]

AMD FX-6300 3.5GHz 6-Core Processor
Asus M5A78L-M/USB3 Micro ATX AM3+ Motherboard
G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1600 Memory
Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive
Sapphire Radeon R7 260X 2GB Video Card
NZXT Guardian 921 RB ATX Blue LED Mid-Tower
EVGA 500W 80+ Certified ATX Power Supply

 

[ben12144]

Specs?

AMD FX-6300 3.5GHz 6-Core Processor
Asus M5A78L-M/USB3 Micro ATX AM3+ Motherboard
G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1600 Memory
Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive
Sapphire Radeon R7 260X 2GB Video Card
NZXT Guardian 921 RB ATX Blue LED Mid-Tower
EVGA 500W 80+ Certified ATX Power Supply

well i know know the green light means its on standby power i guess