Cannot access localhost(phpmyadmin) because of username & password

How can I reset the username and password, I have already reinstalled wamp server but no luck.

From serverfault

• if I remember correctly, then by default PhpMyAdmin uses mysql authentication to see if you are allowed access.

  this might well be different from your root or admin account on the machine (although the username is likely to be 'root')

  if you need to reset your root MySQL password, then the MySQL handbook should help :)

  From MidnighToker