I have 2 user profiles on my XP machine. One is my own account, the other is a guest account. I bought an external hard drive to back up my files. After I backed them up, I can now view ALL of my files on the external hard drive from the GUEST account! That's not what I want. How can I prevent a guest user from seeing the external hard drive at all?
Thank you.

you can create policies and restric user to access folders. I'm not too sure about giving no access to a drive but there may be away. You may want to do a research about users policies and restrictions, maybe under home edition there is not much that you can do - but if you are using XP pro there are more user restrictions that you can apply to the machine. Also there must be a software out there that will help you to increase security or with server edition software you can control better your users.