Steve -

For your Win98 (or for WinME), you might find Q183887 Description of the Windows Registry Checker Tool (Scanreg.exe) helpful. The information there is a bit obsolete for modern versions.

I'd have to check around a bit to find a general description of the Registry for obsolete systems, but in current (WinXP) I think I've seen a description that describes the Registry of consisting of 5 main files that are scattered around in various places. Since any registry changes should be done in Regedit (or for some changes, in Regedt32 in new Win versions) you shouldn't really need to know where the changes go to when you save them.

John