Eclipse can’t see my Android Device on Window.Previously I had been working fine.Suddenly I got This problem.How can i fix this:

I have setuped these thing in my device:
1.USB debug mode:
2.Thick Unknown source
Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
Try this:
Drag the notification bar & click on “USB Connected” then click the button “Turn off USB storage” and “Turn on USB storage”.Then Its ok
You may be clicked this option previously