Make sure you have the 12V 4-pin power connected as well as the 20 or 24 pin main ATX connector. It's the single most common reason for not posting on a new system- overlooking the "hiding" 4-pin power outlet they put cryptically near the top where you dont see it. hehe. (on your new motherboard, it's just above the alluminum heat sink to the side of the CPU slot)
Also, make sure you have all the case lines plugged into the header properly. Also re-orient the memory.. make sure you've looked for which slots to put the memory into as well as remove all cables (ide) and secondary pci cards (just leave the videocard in) while trying memory in singles/different combinations to rule out bad memory.
Also, double check your speaker cable. If there is some other problem, it should be beeping when not posting.
Good luck!