Wireless through adapter and router, won't connect

Actually, my Dell is connecting fine, but another machine on our network is not connecting, and you're all so smart so I thought I'd try for answers here.

He is using a Toshiba notebook with a Linksys wireless adapter card. The machine can "see" the network with 5 nice bars of signal strength. When he goes to connect, however, it just tries and tries and then gives up.

We were all online yesterday, for several months. Due to a storm and some damage last night, I had to reconfigure everything to get us back online. My router is set to factory defaults right now (yes, that's right, no encryption or anything!) until I can confirm we're all operational. Desktop hard-wired connects fine. My Dell notebook with built-in wireless connects fine. His Toshiba notebook with adapter card... sees the network but won't connect.

What am I not thinking of?

Thanks,
Bekbek