Hi,
if you have a fullbackup you only need to check the "overwrite the existing database" option in the restore database menu.
or, with more fun, try this:
To attach a database with lost log file (ATTACH_REBUILD_LOG )
CREATE DATABASE database_name
ON [ ,...n ]
FOR { ATTACH [ WITH ]
| ATTACH_REBUILD_LOG }
[;]
it's on MSDN SQL Server 2005 Online Doku
Regards