I went and bought another router before seeing your suggestion, GermanTux. Picked up a Belkin G for 25 bucks, and all seems to be working again. So the confusion came in when the new Tenda router turned out not to work. Thanks for all the help.
Only 2 issues remain:
1 -- page loads seem slower than they were before. Any settings that might need looking at for the new router/config?
2 -- since I'm not using the wifi part, how do I turn it off and only use the cabled route?
I have to second comments about Radio Shack - their sales force is generally too motivated to make a sale to point the customer at what they really need. Once in a while you find someone there who knows the deal, but most of the folks who work there just seize on the first thing you say to them and know of some vaguely related gadget they think will fill your needs.
Get rid of the Belkin if you want something dependable. A lot of folks may disagree with me on this, but I've not seen anything by Belkin more sophisticated than a cable or cable adapter that was worth beans. LinkSys isn't bad gear since Cisco bought them out, is generally widely available, and I've always been a fan of D-Link's gear. Netgear is pretty good, too, but is sometimes more interesting to get set up correctly.
Look at D-Link's site; I think they even still make a non-wireless model... hang on.
Yup, here it is: http://www.dlink.com/products/?pid=478
Back to your questions:
Most routers these days have a web interface that can be accessed by pointing your browser at http://192.168.1.1
so consult the documentation with your router and see where that is. The very first thing you should do
after your network is working is change the default password for the router's administrative account to something only you know and can remember. This may save you from being pwned
by some bored script kiddie trying to expand a botnet. If you're really paranoid (and I'm not, myself) you can also change the address of the router to something less obvious, but it's not really necessary as long as you use a strong password and don't share it with anyone. (It might also mean having to change the setup in your modem, too...)
After you've secured your router with a new password, look around in the web interface menu at the options you have. Different router manufacturers have varying ideas about how to organize and set up their equipment, so it's best to get familiar with the interface before
making too many changes. Without knowing your specific router's model number, the best I can do for now is point you at:http://en-us-support.belkin.com/app/product/list/q/routers/
I kinda bumble through networking, myself. I have to break out the books a lot when it gets interesting. This site
is a decent intro to how routers work in general.
Here's one thing I do know: if you use BitTorrent for anything, look at limiting your upload speeds and max number of connections in your client (example BT clients are Ktorrent, Transmission, and Azureus - there are lots more, too). Otherwise, the sheer massive number of connections BT uses will swamp your router's routing tables and slow things down. Sounds like this may not be an issue for you, though.
I hope you get things moving the way you want. I gotta get ready for work just now, but maybe someone else out there will have some ideas?