actually, the system isn't starting at all it sounds like, only the power supply is turning on (and therefore fans, hdd spinup). I would verify that your board supports the cpu, and if a bios rev is needed, then your gonna need to find a cpu that will post with the current rev in order to update.
Double check all connections are secure, especially the 4-pin cpu power. Also, disconnect anything that ins't required to boot such as optical drives, addon cards, usb ports, etc. Use only one stick of RAM as well. Clear the CMOS and then try to boot. If it still doesn't POST, try to borrow a different power supply and see if that works. If none of that works, you either have a short somewhere on the case, or your motherboard is bad.