XAMPP and backup files

[cardriver]

Hi,

My problem is, that after I have downloaded backup files from my host I get this message when I try to view the site on the local server:
Database Error: Unable to connect to the database:Could not connect to MySQL

I have viewed a complete new site in XAMPP without problems so I guess that my problems with the old site in XAMPP has something to do with passwords, naming or the like.

Could anyone help me a bit further. And give me at step by step guide?

[caltuna]

What do you mean by "backup files"?