When clicking on Firefox, it says server not found, if I click on IE it says not connected to network. We just replaced the AT&T modem because last one fried. If I manually turn off computer at TOWER and reboot it will usually work but not for long. The wifi works fine with our hand held devices so I know AT&T won't help. No issues with previous modem, I didn't change anything with the connections or the computer itself. Any ideas on how to resolve or troubleshoot this? Running windows 7 on a hpDo you connect CABLE or WIRELESS?

Remember that this is a different modem even though same service so the SSID and the Password will be different.

You will probably need to ACCESS the modem with a system via cable and configure it for you settings.How would I do this? I didn't see anything flagged in device manager. When I went to network settings and troubleshoot devices, nothing happened. Not sure where to go to configure modem. You will have to connect via cable to the modem and open a BROWSER window and type in the IP address of the modem.

From what I can find on the ATT site should be:

Type 192.168.1.254 in the address bar and press the Enter key to log into the modem's interface.Did you try deleting the Network and re-creating it in Control Panel/Networks ? ?