I installed a Windows SharePoint Services (WSS) Web Front End (WFE) onto an external server to be used for the External Collaboration Tool-Kit.

Once I got it installed I ran the SharePoint Products & Technologies Configuration Wizard and received the following error:

Failed to register SharePoint services.

The log pointed to several different registry keys located at HKEY_LOCAL_MACHINESOFTWAREMicrosoftShared ToolsWeb Server Extensions12.0WSSServices.

I deleted everything under that location and it completed successfully.