Both computers have the same account names AND passwords.. except the desktop is the administrator (owner), but the laptop isn't the owner but has administrator privileges.
This is the setup: MSPaint drawing of setup
One computer, the desktop (A), can access the shared files from itself (duh) and the laptop, but the laptop can only access it's own files, not the desktop's. I can ping the router from both computers, but the laptop cannot ping the desktop, and the desktop cannot ping the laptop.
When the laptop TRIES to view the files on the desktop, it gets the permission error, etc.