Netbook not visible on HomeGroup

Hi there. Got a netbook that is part of a Home network. It just isn't visible on the home network. It's got the same info as far as group, like HOME. It can see the two other PCs on the network and access their shared files, but it isn't visible by the other two. The only difference is that it is wireless. The netbook runs win 7. One of the PCs runs win 7, the other xp. Everything runs fine between the two PCs. The netbook has the network discovery turned on, has files that are shared. Crazy... Can anyone help?

Found out that my netbook was password protected. For some reason that must make it invisible. When I removed the password protection, it was visible.