My laptop webcam is not working- lenovo

Friends,

I’m using lenovo laptop. im my laptop webcam is not working. i’m using the sonne screen capture software. It shows the error message[” Device not found. Please connect it successfully”] I have reinstalled my driver softwares using driver cd.
When i use video chat with my friends, at that time also it is not working. it shows just my profile picture. After re-instalation of softwares, it started to work after 5 days. but only for few mins. Please give me the solutionfor my problem.