I've been running two desktop computers (Windows 7 ent x64 on both) and a networked printer on a very old 4 port network switch for several months now. The switch is connected to a wireless router, and the switch is for things without wireless capability. The computers on the switch are on a completely different network than the laptops on the wireless router, though. I believe the switch acts as it's own network instead of becoming part of the network of the wireless router. I had both desktops joined in a homegroup because I have some music and other media on one that I wanted to share and stream to the other, which is hooked up to a TV. That worked for a while, which surprised me because the switch is only a 10/100 and I was streaming a some movies that were 4-6GB files. One day, though, the homegroup speed randomly dropped to ~3 KB/s, not even enough to copy over a Word document or anything. The computers still both showed up in the network, but the speed stayed at that level. Since then, it has been impossible to stream anything, so I stopped for a while.
The other day, I picked up a Rosewill 8 port gigabit switch, hoping I could get my homegroup running again, and with a faster, newer switch, be able to stream everything without issue. I got it all plugged in and hooked up just like the last one, but it isn't working quite right. It appears to be set up to pass through devices to the wireless router, because if I try to go to the IP for the config page, it takes me to the wireless router's page. The printer and one of the desktops also now show up in the network of the wireless router. All of the laptops see them, and I can connect to the homegroup on the wireless network with them. The other desktop (the one with everything I want to stream on it), however, appears to work the same way, but does not show up in the network list of any computer, nor does it show any other computers in its network list. Both computers connect to the internet just fine, and as far as I can tell, everything is set up identically. I've tried removing and adding the network on both desktops, and it always comes back to the same thing. Seems to me that since they are both plugged into the switch, they should at least be visible to each other. The desktop with the media always wants to create its own homegroup, even though there should already be one there on that network.
I'm not sure if that makes a ton of sense, but I've been working at this for a couple hours and nothing I can think of works. Any thoughts would be appreciated.