Linux/XP networking conundrum [SOLVED]

[#1]

Two laptops and a router:
Windows xp home sp2 with ZA
Puppy linux 2.16 with Samba but no soft firewall
DrayTek 2800VG with DHCP
Originally LAN setup with XP wireless and Puppy wired. After a bit of fiddling it all worked fine. Shared directories accessible in both directions.
On XP,  windows explorer allowed me to browse to the samba share.
Tonight tried it again only to find could no longer browse to the puppy. What's the difference? -- I'd changed over from wireless to wired on the XP box and disabled both the wireless card on the XP lappy and the  AP on the router.
If I re-enabled wireless it all sprang to life again ... and I can't work out why this should happen. 
my smb.conf doesn't have IP or subnet restrictions set btw but does have "local master = yes" set.
Any suggestions from you networking gurus out there?
Paul

[#2]

Disable ZA and see if it works then.
On several occasions, I had to add the other PCs IP in the trusted zone of ZA before I could access file & print sharing on it so maybe try the same. Switching between wireless & wired may have got ZA confused as it would see different local networks.

[#3]

Sorry should have said I tried that and it made no difference (it's disabled right now and I can't see the puptop from XP)
Even with ZA enabled, both are pingable from each other, and I have an FTP server on the puptop that I can reach from XP, so it's not an IP networking issue.
ah ... light is dawning ...

[goes away and fumbles around a bit for a few minutes]
samba implements netbios within tcp/ip, so I've just checked to see how netbios is setup in tcp/ip advanced properties in both XP adaptors; and of course netbios over tcp/ip is disabled in the wired adaptor and enabled in the wireless.
I'd disabled it as a "security" measure ages ago but had forgotten to do so in the wireless.
Just reenabled it for the wired adaptor and its sprung into life.
Should have thought of that last night but I was knackered.
thanks for the attention anyway Peter
Paul