Access Denied on Windows File Sharing

I'm going to be as clear as possible when explaining the situation. I'm also going to try to list the steps I've done to do important tasks. But, the problem I'm having is that on my network, I'm having issues getting files on my computer to be shared on other computers on the network (Virtual or otherwise). My computer will be the one I'm currently on. Other computers would be computers connected through my network.

My computer is connected to the router through a wireless connection. I am able to connect to the Internet, ping the router, and ping the other computer. (All of this should be obvious seeing as how I'm able to connect to the Internet.) My other computer is connected to the Router through a wired connection, but the other computer is not always turned on. I have File Sharing enabled on my computer. I also have it enabled on my other computer. My computer is able to view the other computer's files (when my other computer is turned on). Through the Virtual Private Network, I am able to view other computers connected through the network.

The problem is that other computers are not able to view my files, coming with an error message that access is denied (I can't remember the exact wording of the access denied error message, but it basically states that I need to contact the administrator to see if I have permission--I am the Administrator of the Network).

My computer is running Windows XP Home SP3 while the other computer is running Windows XP Media Center (I think SP3).

In the Network Connections settings, I have different options.



(Hamachi is what I'm using for VPN). Note that the two disabled Network connections are this way because they serve no purpose (though I don't know what the 1394 connection is for).





As you can tell by the screenshots above, I do have File and Printer Sharing for Microsoft Networks enabled for both the VPN and for the wireless networks.



The folders I want to share look exactly like that (they have "Share this folder on the network" enabled, but "Allow network users to change my files" disabled) and each folder has a different name to them.

I've tried to disable Windows Firewall, but it was not successful.

I'm at my wits' end. I know I've set everything up correctly, but I don't even know where to begin to troubleshoot. I've even done some generic troubleshooting that I've found on the web (I've even checked here for help, but no avail).

I hope this is enough to start troubleshooting, or to get me into the right direction. If there is any questions, or if you need some clarification on something, let me know and I'll try my best to answer them.

Thank you for your help in this matter.

EDIT 1: One thing I have tried, but not yet tested, is to edit the Regedit with the following:
I haven't done the reboot yet to see if it changes.

I've run into these sorts of problems before - can't remember the solution offhand though. But, do you need to enter a password to log on to your computer? It could be that remote users need to Login to access it and/or you need to set up a "guest" account. Or some crap like that.

To answer the question, Quaker, yes. For security purposes, I enter a password to log into Windows. I have fixed the issue (I've posted the instructions above). Thank you for your help.