Bad Mobo, or bad CPU, or what?

My PC won't boot. The PSU seems good for it makes power the led glow, and runs the fans. The system has an 'Asus A8N-VM rev 1.01' mobo and an 'AMD Athlon 64' processor.

Symptoms: (1)The SATA HDD doesn't make any vibrations or noise. HDD LED doesn't blink or light up.(2)The CPU fan runs, but the CPU sink doesn't get heated.(3)No beeps (I couldn't locate the little speaker, didn't know if it came with one, looking for the pins to connect a speaker).

Any help?

 

Correction
My PC won't boot. The PSU seems good for it makes power the led glow, and runs the fans.
about the PC: OS Windows XP SP3, Processor AMD Athlon 64, Motherboard: Asus A8N-VM rev 1.01.

Symptoms: (1)The SATA HDD doesn't make any vibrations or noise. HDD LED doesn't blink or light up.(2)The CPU fan runs, and the CPU sink gets heated.(3)No beeps (I couldn't locate the little speaker, didn't know if it came with one, looking for the pins to connect a speaker).

Any help?

 

I tried clearing the CMOS. And stripped the system down to the bare minimum, viz. processor, motherboard, 1 GB RAM card, PSU and the monitor. Still ain't anything on the screen.