Hi Luisa,
when installing osclass on your wamp local host, dont forget that you first need to create a new database, and then during installation, the scrit will ask for user name/password for database access.
To create your database, just go into your wamp control panel, select PHPMyAdmin, click on DATABASES, click on CREATE, select the name for your database, and you are done.
If you forgot your user name/password for your MySQL, .. usually when you create your first project in wamp, by default it sets the user='root', and password is left in blank, so if you haven't create your user/password when you first installed wamp, then it is more likely that it is the defaults settings ( 'root' and 'blank') .
If it doesnt work, go to PHMyAdmin panel, select your new database, and click on PRIVILEDGES, you will see a list of all the users allowed to read/write your new database, the first one should be your username, then click on EDIT PRIVILEDGES, scroll down a bit, and you wll see your password.
Hope it helps.