Computer not booting

[iGeekOFComedy]

So my computer wont turn on. It's a custom gaming PC. Everything is plugged in because theres a light on the motherboard like usual but when i push the power button theres nada.

EDIT: flicked cpu switch and nada

EDIT:2 smell coming from back like slight smell of gas.

PSU = 1K Watt OCZ

 

[johnb35]

Start by replacing the power supply. If it smells, its most likely bad.