MySQL :: MySQL 5.0 Reference Manual :: 2.10.6 Upgrading MySQL on Windows

You do not need to uninstall the service Simply change the my.ini file in C:\windows\my.ini Then copy the new mysqld-nt.exe to the oldversion/bin/ folder. Change the line basedir=C:/apache/mysql to basedir=C:/apache/newversion for example or whate

dev.mysql.com