Instructions
Switch your PlayStation 3 off to reset it. Switch off and turn back on your wireless modem.
Turn on your PlayStation 3 and navigate to the left. Select "Settings" followed by "Network Settings." Highlight "Internet Connection Settings" and select "Yes" to continue.
Select "Custom" in the menu that appears. Select "Wireless" followed by "Scan" and choose the source with the strongest signal -- the higher the percentage, the better.
Press "X" on your joypad to continue and select "WEP.' Locate your WEP key which can be found on the back of your modem or will be printed on a plastic card that came with the modem. Enter the WEP key.
Select "Automatic" and then select "Do Not Set."
Select "Manual" and then enter "4 2 2 2" in the Primary DNS type box and enter "4 2 2 1" in the Secondary DNS type box.
Set "MTU" to "Automatic." Select "Do Not Use" for the Proxy Server setting. Choose "Enable" for the "UPnP" option.
Save the changes and wait for your PlayStation 3 to sign you into your account automatically.