Hello. I moved my computer downstairs and it will no LONGER bring up a web page on IE or Mozilla Firefox.

Computer:
Dell desktop
windows xp pro version 2002
service pack 3
intel pentium 4 cpu 2.80 GHz

I have cable internet using a modem from Comcast. My wireless ROUTER is a Linksys and I use a Wireless-G USB Adapter. Upstairs I used the wireless connection to be on the internet. Now that I have moved the computer downstairs I would like to connect it via an ethernet cable to the wireless router. (This worked just fine on the computer that I had at this desk until yesterday.)

The Local Area Connection SHOWS as Connected at 100 Mbps. When I try to browse to a web page it says "Server not found."

I have rebooted the modem, router, and computer. Other computers are working perfectly (one via wireless and the other is via ethernet cable). I have changed the jack that I am plugging into on the wireless modem. I have checked everything I can think of to check and I am stumped. I would really appreciate any help anyone can offer on this.
Thank you,
Jackie

**ETA: I just plugged the ethernet cable that is hooked into the desktop in QUESTION into my laptop and it connected to the internet. It is clearly something to do with the desktop but what could it be?1.  "ipconfig".  From a Command Prompt on the desktop in question, enter the following commands (without the quotes).
     a.  "ipconfig"
     b.  "ipconfig /all"                        ; note the "space" preceding "/all".
     c.  "ipconfig /all > IpcfgAll.txt"  ; note space before "/all", ">", and "IpcfgAll.txt"

All three commands display information about the TCP/IP configuration of the desktop.  The first one displays summary of the most important information.  Second command displays "all" the data.  Third command redirects all the data  into a "text" file within current directory from which command is executed. (If desired, you may specify your own complete file name path for that text file to store it where ever you wish.)

Please "post" the output of the third command in your reply.  You may use "notepad" to view the contents of the output data (and cut and paste from there).

2.  Command Prompt Window.  To access a command prompt window:  Start -> Run -> TYPE "cmd" without the quotes and press <Enter> key.Thanks for the offer of help dahlarbear.
The IT guy at work had me change the TCP/IP DNS numbers and that fixed the problem.