Do i need another motherboard?

[Dezurik]

System Manufacturer: Hewlett Packard
System Model: HP Compaq dc7700 Small Form Factor
System Type : X86 based PC
Processor: Intel(R) Pentium(R) D CPU 3.00GHz, 3000Mhz, 2 Core(s), 2 Logical Processors(s)

My computer's graphics card is a Intel(R) Q965/Q963 Express Chipset Family
I recently bought a R6570 MD1G/LP graphics card, and a RX5300SS ATX Power supply
The power supplies main connecter is a black 20+4 main connecter, the motherboards output is a 24 connecter but its white, and its smaller than the black one, doesn't fit.
Sooo what do i need to do here, buy another power supply, another motherboard?.. and if i get another motherboard will everything else in my computer fit onto it.

 

[o1die]

If this is your power supply: http://www.amazon.com/Nexus-RX-5300-Efficiency-Quiet-Supply/dp/B002R26GNE then your hp board must use a proprietary ps, since the nexus is a standard atx form factor. If your old power supply still works, I would save the video card and either sell your old system as is, or use it for a spare. Time for a new system, since your new video card may not even work with your old hp motherboard.