No Boot

Hello all,
I need some help because my mind is drawing a blank, I have my desktop that is not booting or going to POST, the specs are:
Lite-On DVD+/-RW
MSI AM2+ DDR2 Motherboard
AMD 7750 Athalon X2
2x 2Gb DDR Ram
Nvidia 9400 GT Video Card
Westinghouse 500Gb Sata HDD
Katachi 500GB SATA II HDD
Maxtor 160GB HDD
Omega 700Watt Power Supply
Logitech Wireless Keyboard & Mouse

Now the Problem is the computer has power because the HDD's are spinning, so are the fans and LED's, but it is not starting up, no POST no going to BIOS, only no signal on the monitor, now I have included the Logitech Wireless Keyboard & mouse, because previously when I turn on the computer the wireless reciever for the Key/mouse blinks all three lights befor the computer goes to BIOS, but when I turn on the machine no lights.
Can anyone help. Is it the motherboard or is it grounding somewhere. I may try and change out the groundings for the motherboard if i get no reply from this forum. I have Security + class in the morning, and CEH this week, so my time is limited, any help will be Very much appreciated.

Thank You in advance