I also ran into this problem. One day, I suddenly couldn't see any APs in my home, but could elsewhere. I chalked it up to the N problem but didn't go much further. I don't really use my tablet much at home.

It was sort of confirmed when I went to a friend's house and also could not see any available connections. I asked if he was running N, and he confirmed. He turned his router to G and unhid the SSID, and I was in.

I remembered someone saying that they could connect if they stored the SSID and parameters in Connections. I guess what pablob mentions above, also. Just today, I tried it. Well, actually with a neighbour's open connection. I went to Control Panel/Connectivity (OS 2007 HE) and entered in a name, the SSID, etc. and saved. BOOM! I could then see a bunch of APs. I could even refresh and they'd come back. I connected just fine.

The funny thing is that once I disconnected, I could no longer see any. Back to the way it was before. But if I go back into Connectivity, edit and scroll through the saved connection and re-save, I can see them again and reconnect.

Not an exhaustive test, but I tried this disconnect/edit/save process 3 times with the same results. So I think I have a workaround for known APs.

This won't help of course if you're in a strange place and scanning without knowing what you're supposed to be hooking up to though. But it's better than nothing. Hope it helps.