It is a dos command that allows you to see the services that will load when the system is booted. This is run in recovery mode from your Microsoft operating system CD on win 2000 and XP.
Listsvc
C:\> Listsvc
1. true 2. notify me but dont automatically download or install them 3. scanstate 4. dual 5. activation 6. active directory 7. system 8. 64 9. device manager 10. drive image 11.hidden recovery 12. automatic 13. virtual 14. distribution 15. client/server