mysql problems

[porcupine]

Hello guys
Here is the problem. You may find it trivial, but it is a serious obstacle for me. I make a database, a table in mysql and it goes fine.
Then I try to view my table with PHP. I am pretty sure that I can't connect to the database.
In particular "$db = mysql_connect("localhost", "root", "") or die;" statement doesn't seem to be valid.
Should I use another username, password or both? Are there any suggestions?



Trying to solve the previous problem I face a new one: My new username is not anymore "root", but "root@localhost". This happened during a phonecall assistant by a friend. How did this happen? How can I generally change my username?

If the previous explanation is not clear all I mean is: when I try to access mysql the: "mysql -u root" command is not valid. Instead I get this message: "access denied for user: 'root@localhost' (Using password: NO).

Thanks for the cooperation