The state of the system when I started was that there was a single, working instance of Oracle Database 9i. I proceeded to install Oracle 11g choosing to Install Software Only. Upon completion, everything still worked fine. I created a new 11g listener on port 1522 called LISTENER, which was the same name as the 9i listener listening on port 1521. I don't know if things still worked at this point. Next, I started creating an 11g database which I gave the same SID as the pre-existing 9i database. The database creation process failed at first, and I didn't read the error messages. I ran it again, and no error messages came up. It was at this point when people started complaining about being kicked out of the database.
Upon investigation, I found that it was completely impossible to connect to the once flawless db instance. I tried a myriad of things to get connected to no avail. Finally, I decided I would be better off creating a separate instance and accessing the datafiles from there. This is what brings me here. I have tried creating an instance with the same datafile names and copying the originals into the directory, but I don't know what the original configuration is so that inevitably failed. If anyone has any advice on how I can gain access to the datafiles without knowing the original configuration, I would greatly appreciate it.
OS: Windows Server 2003 R2
Pastebin of 9i alert.log here.