Alright guys, got quite a confusing problem here.
I'l start with my PC specs:
CPU = AMD 64 x2 5000+ (2.6ghz)
GPU = nVidia GeForce 8600 GTS
RAM = 3GB 667Mhz made up of 2x 512mb and 1x 2gb
HDD = 7200RPM Sata II 120GB and a 320GB HDD
PSU = 400W
Right, i've just upgraded my motherboard from a Phoenix M2NS-NVM to an Asus M3N78-CM. I have all my hardware plugged in fine, when i connect the power cord to my PSU the LED on the motherboard shines green, i press the on switch to turn on my PC but nothing happens, no fans, nothing boots up, moniter stays off... Nothing. It feels almost like the power cable on my on/off switch isnt plugged into the motherboard correctly when i know it is.
The problem cant be my PSU because it worked perfectly on my old PC, I have also tried another PSU (250W), still nothing.
One possible cause that i highly doubt is the cause... is that i have only plugged in my powersw/ground cords into my motherboard from my on/off button, the reason i havent plugged in the cords for the other things (HDD LED, System Speaker.. etc) is because they dont reach the position in the motherboard where they are suppose to go.
Any help will be greatly Appreciated. Thanks.