>I sort of am the dba, the system was set up by a real dba but he's gone. Can you tell me exactly where to find this thing?

On the Oracle server, start in the Oracle home directory. Look for a path near the root of this directory that looks like:

app\oracle\admin\some_name_here\pfile

The key is getting to the PFILE folder. there will be file name like INIT.ORA of INITsomething.ORA. Open this file with Notepad but do not change anything. You will find probably everything you need [db name, domain, etc].