dear ronak,

if you forgot or loss your kvpy user id and password then you can retrieve your user id in the forgot user id section and you can set your new password by going through the forgot password section provided in the inteface.In both case you will receive a one time password in your registered mobile number or email id.By providing the otp you can set your new password.

But at first you need to check you registered  email id because after registration they sent a confirmation message where the user id and password is also given.