This suggests that you have changed the password for the 'root' user in the mysql database but have not changed the root password in the phpMyAdmin config file.
If this is what you have done try the following:
Look in c:\wamp\apps\phpmyadminx.y.z\config.inc.php
I'm pretty sure I changed the password, I went under privileges and changed it under root. Ever since then I keep getting error msgs. I even tried uninstalling it, but nothing works. I feel very mixed up with all the changes i've tried to effect.
Uninstall WAMP using the proper uninstall in Control Panel -> Programs and Features
Then make sure the c:\wamp folder and everything in it is deleted. Wamp uninstall keeps things you may have changed so the delete of the folder and all its sub folders is important in your case.
Then reinstall.
This should start you off with a completely new WAMP environment.