Vista in wireless network

I have 7 computers in my home network. It is a mixed setting, with some laptops (4), some desktops (3): some wired (2) into the router, some on wireless (5), and some with Windows XP (5) and some with Vista (2).

All of this works generally fine, except for one thing: I have one Vista laptop on wireless, and the transfer speed beyween it and the rest of the network is hopelessly slow. Internet access is fine, only transfering files inside the network is MUCH slower than between the XP machines. Also, if I wire the Vista machine, the transfer speed is fine. I also tried with my regular Vista desktop, which normally is wired, but now temporarily on wireless, and the exact same thing happens.

Can anyone explain this?

All help much appreciated.

Jemoto

 

First, are you too far away from your router?