Ga-ep45-udr3r stopped posting

Hi
I built this machine in june probably my 10th build, anyway this computer was left on and when i got home from work , could smell burning of course went to the computer and well that was it. shut it down opened the case, lot of dust so i cleaned it out , tried to start it later in day nothing the phased lights came on for a sec then nothing. I put in a new psu after a few on and off swiching of the psu evrything came back on all fans hard drives spooling up, Phase light all stay on, and no post cpu fan is only fan not running. Read manual it does not say much about the lights. if they stay on does it mean no power to cpu? since the cpu fan does not work does that mean i need a new mb? or do i need both cpu and mb? It is obvious i had 2 problems psu and something else. will the cpu fan not coming on keep mb from posting? If i just change the HS could that fix it, I ask that because i don't know how just doing that would work, or clearing out cmos if the cpu is fried will the mb be ok and vise versa or should i just get both? I hate asking question because i can never word it correctly, I guess if i new what the lights were i could figure it out
Thanks
Rich

I did actually switch the cpu fan to the system fan 2 ( forgot to say that earlier) and still nothing. so I guess I can gather from that, that the board is toast
Thanks for your replay
Rich

No problem,, and thank you for the help