I have a home network with a desktop running XP hard wired to a wireless router, a laptop running XP and using a pen type wireless connector, and a laptop running Vista with built in wireless connector.
The hard wired desktop shares files and connects to the internet, all as one would expect.
The XP laptop similarly shares files, connectes to the internet and uses the printer attached to the desktop.
The Vista laptop connects to the internet until its been standing idle for a while, and then nothing will persuade it to reconnect. The only way to reconnect to the internet is to reboot.
Sometimes the Vista laptop will see the other computers on the network, and on special once in a blue moon occasionas, lets you use the printer on the desktop, but more often than not seems to think its all alone in the world.
Vista's network diagnostic tool just returns 'unable to diagnose fault'
Don't want to hard wire this too, as it defeats the object of having a laptop, but I see no other option, unless someone comes up with a solution to stop this.