dell inspiron 1440 integrated webcam not working.

I have the Dell Inspiron 1440 and my webcam has been working just fine. But this week it's decided to stop working. When I bring up the webcam central it either A: doesn't come on. it only shows a blank/black screen. The light indicating the webcam is on doesn't even light up. or B: the light indicating it's on comes on and then 2 seconds later my PC comes up and says: Your PC has found an error and will restart. :(

I don't know what to do. I've tried everything I can think of. I have an important exam tomorrow that needs a webcam and now I have to cancel it because I don't have a webcam. PLEASE help me. Thank you.