Screwed up permission(s)

I have XP Pro networked to a NT 4.0 server. There are 3 accounts on the machine: Administrator, Gary, & Mama Luce’. I have somehow messed up the permissions on all of the accounts. I get an error message when I try and access Word XP & My Word Documents: “Permission denied. You do not have proper permission to access this folder, file, or service.”
How can I reset the permission(s)so that all 3 accounts have “Full Control” of everything? This whole mess started when I tried to set the permissions for Mama Luce’to full control and the Word exe file to full control.
Please help! My wife needs to access her documents through Office XP.

Thank you,

GSadow