hey guguloth,

Dont worry.If you don't have /lost your hall ticket and application details you can get it., 
The registration number will be send as message to the registered mobile number. 

The application form will be downloaded once ,you finish the application, so check in downloads in pc through which you have applied. 

If you don't get in the above ways: 

You can download fee payment status by 12th hallticket number and dob
In that you will get payment id and may get application/registration number. 

if this does not help then let me know..i will definitely try other way to help you.

all the best!