Imovie 9.0 plays video but there is no sound
I am using Imovie 9.0 bc Imovie 11 won't allow me to make videos over 15 mins long and I am recording weddings.
I have uploaded several videos to Imovie 9.0 and wen't back to edit them and they are playing but there is no sound.
Please help me!!!!!!
iMac, iOS 7.1.2