OK we are getting somewhere. First of all, there are about or 50 or more C2D cpus. Just because the board supports c2d does NOT mean it supports yours. Bios revisions are released quite often to support newer models of the cpu; ie 9xxx series and the 8xxx series are good examples.
Next you cannot install a new motherboard and expect xp or win2k to boot. Vista is better at this than the older os however it sometimes has problems also. If you want to move an install to a new system/motherboard, there is a procedure to follow. Just installing the board most likely will result in a no boot situation [as you have seen]
FWIW, I would do a clean install of whatever os you want; ie vista, xp, whatever.