Yes, you haven't "shared" anything. Right-click on the folder to be shared. Select the link that says it's a security and you understand the bla bla bla. Share the folder on the network, without using the wizard. XP doesn't like you to do anything without a wizard, or it doing it itself- FYI.
Once it sets the permissions, you should be able to access the other folders. You can do the same thing with the drive, so you can see and modify every folder. Keep in mind if your laptop has the C drive shared, any other network you hook it up to will be able to see everything. You can get around this by giving the workgroup a unique name that only you know...