>i just bought a new server for my company, and i want to transfert my sql server express 2005 to my new computer, how can i do ???

Robert,

Check in the documentation for detach and attach. The idea is:
1. detach your database from the original server
2. copy your files to their new location
3. attach your database to the new server.

This is rather easy to do with SQL Server Management console. Don't know if it comes with the express version.

José