Okay, sorry. That was funny, but I'll explain: the Windows registry is a core component of Microsoft Windows. Programs store data there, along with Windows, on how to behave, settings, how they run, what they do etc. In the case of JJ2, it's player setup, listserver settings and some other things. Seeing as how you know little about it, I wouldn't go fiddling, you can seriously mess up your computer if you don't know what you're doing.