how do fix my webcam?

my webcam is built into my samsung N130 laptop. when i try to send an invotation to start sendind my webcam using windows live messenger it keeps saying We couldn't start your camera device. Please check that your camera is not currently in use by another program, and then try again.ive uninstalled my cyberlink youcam and ive been told to go onto tools>audio and video setuo and enable it ive tried this and it doesnt seem to be working. can you help me?