For the last four weeks I have been on my new Xbox 360S 4GB system to Xbox LIVE without any issues. But today I added a 250GB hard drive - powered off and unplugged powercord before install - and now I can't connect to Xbox LIVE after MANY attempts. I wouldn't think the hard drive would make a difference but that is the only change to the Xbox or my internet service since it was working fine.
The system connects to my wireless Linksys router and the Internet without problem. I can login to Xbox LIVE on my PC as well as anything else on the Internet via the same router and cable modem.
What Country/State/Province do you live in? USA/Florida
Modem brand & model number: **** TM7222G/CT for cable, internet, voice
Router brand & model number: Linksys WRT400N
If Wireless, are you using a white or black external adapter, or an internal (Xbox 360S) adapter?
Is UPnP Enabled? Yes/no/Unknown yes
Do you have a NAT error? If so, what is your NAT? no error and no forwarded ports
Any Error Codes you encounter: internet connection is ok but can't connect to Xbox LIVE
Who is your ISP(Internet Service Provider)? Comcast
After you run "Test Xbox LIVE connection" press “Y” for "More Info”. In the pop-up that appears, what are the following values, if shown? (If a value below does not appear for you, just leave it blank.)