Lastnight I heard a Loud crash. I went in my sons room and all of his drawershad fallen out of his dresser. Nobody was in his room at the time.

Has anything else happened ?
For all the drawers of a dresser to fall out at the same time is at least unusual but not necessarily the work of any paranormal activity.

It is impossible to draw any realistic conclusions from the information you have provided.

Keep us informed if anything else takes place and if you can expand on the information you have provided maybe we can be of more help.

Do you have a cat? Is it possible it could have tipped over somehow and dumped the drawers? Martini is right, it is unusual... but I'd need a couple more incidents to begin looking at the paranormal. Keep us posted?