In addition, you will find that when you go to those options as The_Game pointed out, that if you are connected, you will not be able to change the 'Full Name' and 'Email Address' boxes as they will be greyed out. If you want to change them manually via options, then first disconnect from all servers with /quit and then go to options and change them.
Alternatively, type
/fullname New Name and
/emailaddr [email]new@email.address[/email] - next time you connect they will be changed.
This page may also help you set up that section of mIRC, and typing
/help connecting to a server in mIRC.
Hope this helps
Regards,
