What is C:\Windows\system32\config\systemprofile?

This is new in XP. It's a special default profile for processes and services that do not run under a user login.

http://technet2.microsoft.com/WindowsServer/en/library/cbf5e8ab-9df4-4585-b2a7-f14f5e1caa451033.mspx?mfr=true