Webcam issues with msn

hi
i am encountering a problem with my webcam because it doesn't allow me to use my webcam on msn but it allows video calls to go through instead.I installed service pack 2 and it still doesn't help and i also tried using other types of msn but still the problem remains.My webcam is built in and my laptop is a hp pavilion dv5-1250
Could someone please help me solve this problem ,its just not the same not being able to access my webcam