File and print sharing uninstalls after rebooting

I have a XP Pro desktop and a Vista Laptop networked together. I can share
files from the XP machine to the Vista Laptop without problem. I have to
set the Vista Laptop to file and Print sharing for MS networks check box and
install the three components ( client, etc.) every time I reboot the laptop
in order to be able to transfer files from the laptop to the XP desktop.
Transferring from the XP to the Vista Laptop is not affected by rebooting,
only transferring files from the Vista to the XP machine.

Question: How do I get the Vista machine to not uninstall i.e. uncheck the
box, "File and Print Sharing for MS Networks when it reboots or shuts down?

Any help would be appreciated.
Fred