I think you should keep that one
from
»
[XP Pro] Removing SP2 Backup Files"The only other large SP1 item you will be left with at this point is a folder in Windows named "Service Pack Files." Do not delete this folder. SFC and Windows File Protection will use its contents when needed."
Edit: This one i think you can
"C:\WINDOWS\$NtServicePackUninstall$
Cudni