You might try undoing the router-to-computer connection and then reconnecting it.
I has a similar problem when I reinstalled WinXP. It would not recognize my PCTV card. I had to pull out and then reinsert the card for XP to 'see' it. Then, it asked for the various install drivers.
Yes, thank you, I have tried that several times (as well as unplugging the cable modem and the router) -- just tried it again for good measure. No change -- still doesn't find the Network Adapter