I'm reviving and revising this thread. I'll try to keep it short and answer the posts below. My desktop is running Windows Vista Ultimate and my laptop is running XP Media Center. I'm still having the same problem as before where both computers can see each other in the workgroup, but only the desktop can access the laptop's shared files and not vice versa. When I click on the desktop in the workgroup from the laptop, a window appears asking for a username and password. I have no user accounts with passwords set on either computer and don't desire to set one. File sharing is enabled on both computers, Defender is disabled on the desktop and the laptop is running Windows Firewall. I have no admin passwords on either computer. Trying to access the desktop using Desktop\Administrator (which has no password) I get the usual "not accessible" error message saying the account is currently disabled.