You can actually access the registry from PowerShell using the cd command: cd HKLM:\ will take you to the HKEY_LOCAL_MACHINE hive, for instance.

Major hives:

  • HKEY_CLASSES_ROOT
  • HKEY_CURRENT_USER
  • HKEY_LOCAL_MACHINE
  • HKEY_USERS
  • HKEY_CURRENT_CONFIG