First, hold down Control(CTRL) on your keyboard and click on the fallowing link: Router Gateway
. It should open it up in a new tab, so you can read the instructions as you do it. If will ask you for a password, by default it should be blank, so just click on "Log In" You should see a page like..
Click on "WIRELESS SETTINGS
" on the top left. Now click on the "Manual Wireless Connection Setup
" button. That should bring you to...
The option you are looking is listed under "WIRELESS NETWORK SETTINGS
" as "Wireless Channel
". If "Enable Auto Channel Scan
" is already checked up, changing the channel probably won't help. But if you still wish to, uncheck it, and pick any channel. Usually 1 or 11 is the best. If that doesn't work, let us know, theres still a TON of stuff that can also cause lag. By the way, is your Xbox 360 even wireless? If so, is it possible to make it wired?