Computer won't power on -- problem with 4 pin connector / PSU


Oct 23, 2011
Hi Friends,
I planned to upgrated my system so I bought new PSU – Crossair GS600W.
When I plug in both the 20-pin and 4-pin connectors to the mobo and hit the power button, the lights flicker briefly and turn back off. When I have ONLY the 20-pin connector attached (ie, once I remove the 4-pin connector), the power supply will stay on (fan running).
But system is working fine with my OLD PSU – 450W.
The only thing attached to the mobo are the CPU/HSF and PSU.

Please let me know if there is something as my MotherBoard doesn’t support this much of power supply or my PSU is faulty.
HD – Segate – 500GB
Memory 1 – INTEX – DDR2 – 2GB
Memory 2 -- INTEX – DDR2 – 2GB
Mobo -- MSI 945GCMS2L - Gigabyte
Video card – AIT 6770 HD
CPU – Intel Dual 2 Core – E7200 – 2.53Ghz
PSU – GS600 - Corssair