Originally posted by Reaper
The reason I suspect the power supply is because it comes with a 24 pin ATX cable but no cable for the 4 pin CPU power. Bit confused about this one.
Sounds like an old power supply. If it doesn't have all the connectors which are required by your motherboard and GPU it simply wont work.
If your motherboard requires a 4 pin connector for the CPU and the connector isn't on your power supply, then you need another power supply. No point checking other things until that's fixed.