there is multple ways - if you have PHP on your local machine (which i assume u do considering u are using x-cart) get phpmyadmin otherwise you might be able to open up a console in cmd.exe by typing mysql (depending on version and extras that you have used).... i don't currently have it set up but i might do it today - they is always a GUI for MySQL that does it aswell - remember to put a password on root aswell
find where mysql is installed then goto the bin directory and then run the console program mysql.exe - you can change everything here, just might have learn how to do that from the mysql website