How to solve the DSL Gateway connection problem

When I restart my computer or switched to another users, my AT&T dsl wireless gateway disconnects and then reconnects. This happens whenever computer try to connecting to the gateway wirelessly or via ethernet cable. Both have been tried extensively with equal results. I have Windows XP SP3 OS with Media Center update and wireless connection is made via a D-Link wireless bridge/adapter. The gateway is always on. I have uninstalled and reinstalled the AT&T software but the problem still exist.

Help please!

you can only try to debug your own pc:
when the connection is still alive, open "cmd" window type "ipconfig /all"

Work on, until the connection breaks and leave the cmd window open in the background, or open another one run "ipconfig /all" again and compare the results.

If there is any difference, look for occurrence of a all-zero ip-address.
If you find this, try "ipconfig /renew". Otherwise come back with the
difference.

• If you get the same numbers as before, try
• ping <ip-number of your "Gateway">
• ping <ip-number of the "Name server(s)">
• ping some well-known address like www.google.com

Telnet www.google.com 80
You should get a "connected to ..." message.

If you see a failure anywhere on that procedure, Try the above procedure again.

Are you able to see default gateway path after changing a ipconfig /renew.
Try to restart your firewall, or just the dsl modem by plugging off and on again.
Now that definately should not happen, either your dsl connection gets disturbed (though support says it can still connect from their side) or you should try change the network interface in your computer, eventually - if no luck - go for a modem exchange.