[Dr Zauis]

OK..Im going to try to answer your questions.
I dont have much personal experience so my answers are based on what I have learned from the forums itself..
If I am incorrect with my answers I invite anyone to correct me.

First..Its not possible to play an original unpatched version of EQ. Or any unpatched version for that matter..Many people have asked the question
and I guess EQ was patched from the very beginning. So it may not even be possible to start from scratch and create a specific emulator to play that way.
It is possible to play on a private network or even run the emulator and play the game on a single computer if its powerful enough..Most computers of today can probably run both at same time..I guess you will be using something called minilogin for that..
If you want friends to play with you..You will have to use the log in server
for that..But you can lock your server for your own private use..
Im sure a P4 computer has more than enough power to host a server. And even play on the same but you may want more ram. I have no experience in this area so more ram may not even be needed if there are very few players
ever playing..