post #11 of 11
Thread Starter 
The router is B/G only.
However, I think I found the problem. I should have mentioned this before:

The router supports both a main and guest network. I'd set both to use TKIP + AES security protocol. This morning, I tried different configs and found that his laptop seemed to experience problems with AES. I set the guest network to TKIP and the main to AES and now all devices are staying connected (he was using the guest network).

Thanks for the suggestions.