We all like to customize our environments. We do it at home, at work, in our cars, and pretty much anywhere else we can get away with it. When you customize your Windows 2000 or NT environment and applications, the changes end up in subkeys of HKCU, which is actually a link to your SID’s subkey under HKU. Only a currently logged-in user has access to HKCU. It can’t be edited remotely (RegEdit disallows remote user access to HKCU and HKCC), nor can a SID key under HKU be edited while someone with a different SID is logged in.
The contents of HKCU vary more than any of the other root keys because applications store their user-specific settings here too. If Ellen and Joe share a computer, their respective HKCU subkeys can end up looking very different: Ellen might install and use Netscape, Visual Studio, and BoundsChecker, while Joe might stick with Office 2000 and Internet Explorer. Accordingly, in this section I’ll confine my discussion to the most important subkeys of HKCU.
For better or worse, Microsoft included the capability in NT 4.0 (and Win95, too) to associate sounds with system events such as opening or closing windows, logging out, and so on. This feature certainly falls into the customization arena, and application developers can add their own event classes. For example, if you install Microsoft’s Visual Studio, you can get audio alerts when your compilation succeeds, when the debugger hits a breakpoint, and so on.
The event-to-sound mappings are ...