Linksys Fails 2-Way

My Linksys Wireless broadband Router has suddenly failed to allow 2-way
wireless communication. All 3 of my wireless computers see it, like it,
connect to it normally. But only one-way communication to the Router. It
no longer allows these 3 computers to receive anything from it.

Its wired connections are working 2-way normally.

Is there something in the setup I'm missing, or am I looking at a failure?

Regards,

Terry Smythe
Winnipeg, Canada