Homegroup worked this morning - now gone

Let me start by saying I really love everything about 7....except for Homegroups, which I am developing a huge hatred for. I have spent days on this and finally give up. I have 2 laptops and a desktop running the released Windows 7. And a PS3. The laptops and PS3 connect to the network wirelessly, the desktop is wired. Until last night, no matter what I tried I couldn't get them to see each other. They would show up under the Full Network Map view for each machine, but each only showed itself under the Network view, and they would not find each other if I set up a Homegroup. PS3 says that there are no media servers on the network. Yesterday I completely formatted the 2nd laptop to install 7 on it, and low and behold all of a sudden everything worked - media servers on all 3 computers showed up in PS3, they all worked together, I was overjoyed. However, sometime today it went completely black again - back to all machines being blind (except in Full Network Map view, where they all see each other). I tried syncing the clocks, which is the only suggestion Microsoft makes, tried searching the newsgroups, and am out of ideas. Microsoft pushes how well 7 is supposed to be at bringing all your devices together, yet it seems that there are a lot of problems so far in doing that. Any ideas would be greatly appreciated.

Yea that whole network detection thing has never worked properly for me, I just find it to be a huge headache. I stopped trying to deal with it a long while ago.

Yeah, just really frustrated that it worked for a day, then went away.