My camera won't work!?

i have a Canon PowerShot SX110 IS and in the guide it say's to use AA Alkaline batteries, my camera ran out of battery today so I put some batteries in the camera, I think they were the right way up because they were in the same position as the previous batteries. I tried to turn the camera on bu nothing came up, so I tried to slide the battery case open but it won't budge, now I don't know what to do! Please Help!