Strange wireless problem today.

In the six months or so we've been using wireless here from the Netopia 3347wg router, I don't believe there has ever been anything other than trifling problems.
However, this morning, wireless just would not start in Ubuntu or Mac OS X or any other Linux OS on my MacBook. Even after a reboot, still no wireless.
I didn't think any more of it until Killian told me later that his Laptop (Vista) also couldn't connect for unknown reasons (despite a strong wireless signal.
So we called Eircom (our ISP) and the guy recommended:

1. Shutting down the router
2. Changing the SSID from eircom1073 4700 to eircom10734700
3. Changing the Wireless privacy from WEP-Manual to WEP-Automatic
4. Restart router

After that everything worked fine again.
I talked to the guy to try to see what exactly he had done and why. However, he didn't articulate a very convincing explanation but it did, nevertheless, work.