YARG Filesharing has stopped

I'm running XP Pro and I had filesharing open and working so that I could easily move things around on my network.
Now I am unable to access my computer through others.

On my system I can see all the computers, and access them without any problems.
And on the other systems I can see all the computers(including mine), and I can access the other computers, but when ever I try to access mine I get the
"\\computername is not accessible. You might not have permission to use this network resource. Contact the administrator of this server to find out if you have access permissions.

Access is denied."
message.

Now, I don't know when this started. There was about a two week period that I didn't pull anything off my system, so it happened sometime in there. What could have caused it, don't know.

I have been trying to fix it, but to no avail.
I have ZoneAlarm, but I have tried turning it's firewall settings off, and shutting it down. I have re-created the network a countless number of times.
Does anyone know how to fix this?
It's pissing me off, and I got to get the sharing back up.

XP's firewall kicked it. Turn it off or set an exception.

XP's firewall is off, and it has filesharing as an exception.
Thats not it.

You haven't touched with any security programs? If there's just one setting that says that such and such a user can't access the share, the share will be inaccessible.

Check your Local Security Policy and try adding a username to your computer that is the same user/pass on the other and then adding this user to all the permissions in Local Security Policy.