handman 0 Newbie Poster

hi just decided to clean the inside of the tower it was very dusty vacumed the inside cleaned all fans and cpu fan plugged everytthing back in and nothing fans start lights on computer and cd/dvd drives light up but monitor is blank and no beeps tested the ram took one stick out then the other still nothing i am running win xp have amd athlon2 cpu dual core and asrock alivenf6g motherboard with on board graphics help!!!!!!!! any one any idea motherboard and cpu abot 1 year old
thanks for any help