I have noticed that when I open Spybot, two new user hives are created in the registry:

HKEY_USERS\PE_C_ALL USERS

HKEY_USERS\S-1-5-21-989957435-3950898390-825838117-500

They are deleted on restart of the PC.

What are these hives and what purpose do they serve?

Sybot 1.6.2.46 XP pro SP3.