Dongle has suddenly stopped talking to my PC ..

Hi everyone ...
Can I pick someone's brains again please?
I have a Netgear router (WGR614UK) which, until recently was chatting away quite happily to my Belkin laptop dongle - usually establishing a strong connection. However, having not used the laptop for a month or so, the connection has now vanished ... and nothing I can do seems to restore it. Have even replaced the original Belkin with another 'Surfing' one. Choosing a wireless network comes up with my 'Automatic' connection (which doesn't do anything 'automatic' until I go searching for it), but then connection attempts show 'Waiting for the network ...' and then nothing else.
If you've seen my previous posts, I must look like (and probably am) a total dummy with these things, but I sure as hell would be grateful for help again.