How do I delete a user profile on a Windows 7 machine that is part of a domain?

You can do it with the User Profiles dialog in System Properties:

• Log in as different user (with admin privileges) than you want to delete
• Open Properties for Computer
• Advanced system settings (on the left side)
• Settings for User Profiles (in the middle)
• Select the profile you want to delete and click the delete button

To clear user local profile via registry:

1. Click Start → Run → Regedit

2. Navigate to the following registry key :HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList

3. Under ProfileList navigate to binary key’s like this: S-1-5-21-3656904587-1668747452-4095529-500

4. On the right side under ProfileImagePath you'll see the profile path.

5. Chose the one with the desired user and delete the long registry key like: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList

You will then need to either rename (preferable), or delete the user profile on disk under C:\Users\%username%

I have developed an unofficial successor to Microsoft's Delprof called Delprof2. It is syntax compatible to the original but more powerful.