Try logging in to phpMyAdmin using the user pma
usually with no password.
If you have the privelges with pma
try and create the root user again from the Priveleges
menu in phpMyAdmin.
Also I found this from a Google search:
http://www.experts-exchange.com/Databas ... 54667.html
I did not test it but you might care to if the pma is not successful.
If it works for you then post back here so others might benefit also.
If all else fails then the general consensus is to re-install.