Technically your ID is not stored anywhere, in the capacity that it's a number stored in a file. Instead, there is a file that "examines" your ID though -- you can access it through the start menu. It displays a window with your ID which you can print or write it down on something (or copy and paste in a text file).

After formatting and reinstalling, you select 'multiplayer' then a window should appear with an ID and a blinking cursor at the end. Delete the existing (randomly generated) code and replace with the one you wrote down or printed. Well that's how I did it.

Edit: BTW, I don't know anything about multiple IDs. Only that when I played using my other OS, it used a different one.

Edited by - Braxton on 14-09-2003 05:32:05