The fun part come when you test the new parts with the old parts....
get a new mobo plug in the cpu fire it up doesnt work? hmm try new cpu in board doesnt work, try in old board doesnt work try another new board doesnt work new cpu doesnt work ok new board and cpu .... haha works. Thus wasting lots of money.
I have done this luckly it was at work hahahaha.
Anyway sounds like the mobo to me.
also when clearing the cmos and having it still plugged in... if you dont have a switch on the psu you just turn the switch off at the mains... ok think people.