Thanks for the reply guys. And sorry for my rather delayed reply.I got busy. Anyway, the lens is now fixed. I have sent it to a service center nearby. They couldn't figure it out and told me it should be sent to another place in another town about an hour away. It reached the place and one guy told me it was something rare and should be sent to japan. But then, after a while they called me back and told me some guy at the lab knew what was wrong and fixed it. I paid around $40 and got it back all nice and clean.