2wire wireless router problem

Hi,

My friend has a small wireless network with one pc hardwired to a 2wire
HP1000 wireless router and then two macs (a imac and powerbook) with airport
cards. Neither of the macs can see the network. The pc obviously works fine
because it is hardwired.

Airport is activated on both of the macs, but no networks appear.

I originally had both of the macs on the network about three months ago and
they worked fine, but one day they stopped and haven't worked since.

Does anyone have any ideas on why this would stop working?

Please let me know,

-Scott