ORAC,
Glad to hear the Mac Mini is working great. Sorry to hear of your wireless woes.
The WEP key should contain all upper-case letters. Which router do you have? On my Netgear 834G, it will generate a WEP key from a password I enter into the router. Perhaps yours has this as well?
As OneWorld suggests, try resetting the password. Before that, you could turn off the security briefly (perhaps with your PCs switched off due to their accommodation for viruses
). This way, you would at least know if the Mac Mini is working correctly over wifi. Then, perhaps reset the password and try again.
I wouldn't bother with the Network Assistant, just access the router directly through its web page setup.
