ok - strange problem that's annoying me

we have a belkin g-wireless (F5D7234-4) - this is a replacement one that my kids had to get when the old belkin died while i was overseas

i have internet access no problems but i can't see any of the other computers on the network - a pain for file sharing and backing up

i have an iBook (OSX 10.5.6)

we have a couple of Windows XP machines and a Vista machine - i used to be able to see them but cannot

i don't know if it's a mac problem or some setting on the belkin (have been through the manual - downloaded from belkin cos the kids threw the paper one out! - and can't find anything)

i do have another mac but the HDD just died so i can't check it for connectivity