you shoudn't need a password if you just installed it.
go to the binary dir of the mysql install
ex. c:\mysql\bin\
and type 'mysql'. it should allow you to login without supplying a username or password.
if the service isn't started you might try typing 'net start mysql'.
once your in, look at the database 'mysql' and table 'user'.
'use mysql'
'select * from user;'
to update: you will want to do a command like
'UPDATE user set user='username' AND password=PASSWORD('password') WHERE user='root';'
Something like that should do it, you will have to double check the where clause because i can not remember the default usernames set during the install.
