My 4 year old thinks there are snakes in here room...Please help me!?

My 4 year old has started flipping out at bed time every night for the past few nights. She is petrified there are snakes in her bedroom. I have never had any problems with her sleeping at all and now this is a constant battle. Every night she screams and cries and shakes terribly because there are snakes in there. I have tried everything I can think of but nothing is working...any suggestions on what to do? Please help me and my daughter.