The name of the server is usually the name of the computer its running on. its usually set via the contorl panel | system - and soemwhere on there there will be a tab which will show the computer name.Failing that find your systems hosts file - usually in windows/system32/drivers/etc
localhost is an alternative name netwrok loopback and will work on virtually all PC based OS's. localhost will work if the process that is talking to the db is on the same physical PC as the db.
No, like most database systems, MySQL has its own security & user privileges. you need to grant privileges to specified users before they can use MySQL.
If you search on this thread for the error message you quoted you will find the answers to what you want. The problem is going to be to ensure that you know the main system user account and password. Usually its all covered in the MySQL installation process. Assuming that you didn't follow all the steps on the installation your system user account will be root and the password wlll be empty.
so what user privileges have you GRANTed, and to what database(s)
what database(s) have you created, have you checked to ensure what privileges have been granted to user quentin, and form what computer / network
what tool are you using to GRANT privileges. I see that there is a copy of MySQLAdministraor available for windows.