Folder and drive protection help needed

[zoggie]

I have a network of 3 PC at home and share them over a
network on the 2 Win98 PC's I can make the shared drives
and folders password protected. So if I want to access
the c drive on PC No.1 I have to enter in a password to
get access.
The problem I have is that 1 machine runs XP Pro and I
can't find a way to password protect the drive or folders
on this machine.
When I access drives from win98 machine on the XP machine
I get a password box up.

Thanks for any help

zoggie