Vista wireless/wired network sharing

Hi,

I've been fighting a bit with a Vista Home network consisting of a
desktop PC and laptop both running Vista Home Premium, and a Canon
MP600R printer. Desktop and Canon are hard wired to a Zyxel 660HW-T1
router, the laptop uses a wireless connection.

Both laptop and desktop can surf the web no problems.
Both laptop and desktop can ping the router.
Laptop and desktop cannot ping each other - either timing out, or
occasionally 'destination host unreachable' messages
Desktop can ping the printer
Laptop cannot ping the printer.
Router can ping both laptop and desktop
The Canon printer is a network printer, and the desktop can print to it,
but the laptop cannot.
When I set up the printer I originally used the laptop, but it could not
find the printer. I then hard wired it in to the router, and it found it
fine.

I've recently set up a similar system, but using XP machines with no
hassle at all.

Network discovery is switched on in both laptop and desktop
All software firewalls are turned off - I've not touched the router, as
I've never had to do anything with it before.

I'm due back at the client over the next few days, and will try my XP
laptop wirelessly (ran out of time this afternoon). In the meantime, any
help would be much appreciated.

Cheers
--
Jim McLaren