Logins some help plz

I have database called 'sco' it has the following users
+ sco_admin
+ sco_publish
+ sco_default
+ sco_config

I had to rebuild the machine this database was running on, and I have attached the db back now I need to make the logins again, however when i try and make a SQL login 'sco_admin' and give it access to 'sco' it says "user 'sco_admin' already exists". Which of course it does. I don't want to delete all the users and reset all the permissions.

So how do I associate SQL Login 'sco_admin' with DB User 'sco_admin'?

I had a look at the help but couldn't make much sense of what I was reading.

Also is there a way to keep the SQL Logins intact with the database??

Thanks In Advance,

Nicholas OrrSolved you have to use

sp_change_users_login