No networks detected while two available

My wife's Centrino laptop just had its hard drive replaced, and I was
setting it up so it could reconnect to my wireless ADSL. Weirdness
ensued.
First it connected straight away to my neighbour's wireless ADSL.
When I went to disconnect in View Available Wireless Networks (which
always
used to show mine and the neighbour's), I got:
"No wireless networks were found in range". The only way I could
disconnect
was to disable the wireless.
Then I temporarily disabled my encryption and Mac address filtering,
re-enabled the wireless and it connected right away to my router
(stronger
signal) but still with nothing showing in Available Wireless Networks.
As
soon as I re-enabled encryption the laptop would just connect to the
neighbour's again, no way to force it to try to connect to mine & bring
up
the password dialogue.

Incidentally, the laptop's MAC address had changed too - when I
re-enabled
address filtering in my router it wouldn't connect until I discovered
and
entered in the new Mac address of the laptop. Changing a HD shouldn't
have
changed this, should it? Does this indicate they've swapped it for an
entirely different unit?

So now the only security I have is the MAC address filtering which I'm
obviously not comfortable with. Any ideas why it should be happily
connecting but showing no available networks? I read a recommendation
to
disable SSID broadcast in the router as a security measure, and maybe
this
could cause the networks to not show up, but I doubt it because [a] my
router manufacturer D-Link told me this couldn't be disabled in my unit
(DSL
G604-T) and [b] what a coincidence that my neighbour would suddenly
disable
his at the same time that mine's gone, when he doesn't seem to know or
care
about security at all! Oh, and [c] the name of my router (or my
neighbour's) shows up in Settings>Network Connections>Wireless Network
Connection>Details when connected.