Thanks Evo,
I forgot to mention that I'd tried WPA, WEP (64 and 128) and still nothing.
You're right about security, of course. Anyway, I can't see many hackers trying to wardrive around here, as one of the networks from down the street is unsecured...the laptop can connct to that no problem (it's tempting, its a 4MB line rather than my own 1MB!)
I'll have to read up about the MAC address thing...