I don't know how to do this in NT but in Unix, you can use 'oerr'.
If you get the error ORA-12541:TNS: no listener
You can get the full description by typing this at the UNIX command line:
oerr ORA 12541
Then you will see the following:
12541, 00000, "TNS:no listener"
// *Cause: The connection request could not be completed because the listener
// is not running.
// *Action: Ensure that the supplied destination address matches one of
// the addresses used by the listener - compare the TNSNAMES.ORA entry with
// the appropriate LISTENER.ORA file (or TNSNAV.ORA if the connection is to
// go by way of an Interchange). Start the listener on the remote machine.
So type "oerr", the three letters in the beginning of the error message then the error number.