Don't edit the registry unless you know what you're doing since you can render a Windows PC un-bootable with sufficient editing of the registry.
Here’s Microsoft’s version:
Do not use a registry editor to edit the registry directly unless you have no alternative. The registry editors bypass the standard safeguards provided by administrative tools. These safeguards prevent you from entering conflicting settings or settings that are likely to degrade performance or damage your system. Editing the registry directly can have serious, unexpected consequences that can prevent the system from starting and require that you reinstall Windows 2000[/XP/Vista]. To configure or customize Windows 2000[/XP/Vista], use the programs in Microsoft Management Console or Control Panel whenever possible.
Reposted from: Windows 2000 Resource Kit Registry Disclaimer Page