OMG! That sounds just like my last weekend!
I recently got a t/x, wii and laptop. I had the t/x set-up no problem but when I hooked up the wii, I screwed something up and couldn't get anything to work, even at one point, my desktop. So...after SEVERAL LONG phone calls and online chats, I finally got someone with my internet service who got me straight.
Type this in your address bar and hit send:
http://192.168.1.1/
This should take you to your routers set up page (at least it does with mine, I have verizon)
In there should be an area for wireless settings. CLick there. If you need a password, and you have not changed it already, the default is often admin for user name and password for password or it is just left blank.
Once you open you wireless settings page, make sure wi-fi is 'on', look for an area that says WEP/WPA or something. Mine is set to WEP. After that, there should be a section where you will see a 10, 26 or 56 number which is you WEP key. Mine is set to the 40 bit hex 10 digit # and my phone # with area code is what I chose as my WEP code key.
Now save your settings. And then make sure the WEP in your t/x matches.
Now, I thought I did these steps (over and over and over) while trying to set mine up and somewhere I must have went wrong. But when the verizon tech talked me through it, and we changed my WEP to a 10 digit vs 26 digit #, all went smoothly!
Hope that helps! I know how VERY frustrating it is!