One of the problems with XP is that the PC writes back to the hard drive at shutdown and some times refuses to close programs.
"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\"
"PowerdownAfterShutdown"
Change numerical value from "0" to "1"
This edit automatically ends tasks and timeouts that prevent programs from shutting down and clears the Paging File on Exit
Remember!!! Make a backup of the registry before you make any changes and I would also advise creating a new System Restore Point before any changes.
Brian