| 1. I assume you have the headset unplugged now.
2. If you have another power supply that is adequate for your equipment try that.
3. Also you can try completely disconnecting any of the drives and any USB devices beyond the keyboard to see if you can just get to BIOS. (Also remove any otehr add on cards such as sound card, etc.) Just try to narrow it down.
Hopefully its just a PS issue. Check the PS for fuses also. | 
