Hello and welcome richyboy.
Please confirm that I understand the situation: You _do_ have root access, ie know root's password, but have removed/lost _some_ of root's MySQL global privileges and/or permissions to access certain databases and/or tables?
Does the root user have any privileges or permissions with the MySQL database and tables? In other words, if you get onto phpmyAdmin (assuming you can - see above), you _can_ at least see a database called MySQL?
I believe users' access/rights regarding MySQL databases/tables are held in the database called "MySQL", so you'll need at least some access thereto.
Note: I find the program SQLyog more user friendly for managing users. Have a look here: http://www.webyog.com/en/downloads.php
Please let us know how you get on.