the database works fine in my com but when i make a copy of the mdf files and transfer it to another com ,the database could not be connected,

the database created has an extension of .dbo, does this mean that the database is exclusively owned by my com so it cant be used by any other coms??

 You need to backup your DB from source PC and restore the same on the destination machine.

that is what i did,,i tried to attach the database to another workstation but the connection failed as the error msgs indicated that the autonamed database is not connected successfully..

The database should have a MDF extension.  Moving or copying it can be done, but you'll need to tell us the database you're coming from, what you're going to and the error you get if you expect any real help.

Jeff

 If you have access to Management Studio or Query Analyzer (in 2000), run the following query:

Server 1:

BACKUP DATABASE <databaseName>
TO DISK = '<path>'    -- (for example: c:\mydb.bak)
GO

go to that path and copy that bak file to second server.

Server 2:

RESTORE DATABASE <database>
FROM DISK = '<path>'          -- (for example: c:\mydb.bak)
GO

That should do it.