Exporting database Oracle 7.3 on Windows NT 3.51
Ok here's what I did:

I was in the ORANT\BIN folder.

I had to figure out what the SID was for the DB. Did that via an Oracle client which I tried to connect remotely to Oracle on the server.

set oracle_sid=a

exp73.exe System/manager file=myexp13xxxx.dmp full=y log=mylog130527.log