Cable modem setup question

[idsnowdog]

Right click on the wireless icon and choose network and sharing center > change adapter settings > right click on the adapter and choose properties > configure > power management and uncheck the allow computer to turn off this adapter setting. There's no reason why your pc going into sleep mode would cause the modem to go offline or the xbox. It should only effect the PC's network connection and not the modems connection to your cable or the xbox connection to the modem.