You need to get an app, that either comes with your wireless card or find one online, that shows you what channel you neighbors are using, if they are. If you and your neighbors are broadcasting on the same channel, it could cause problems...
This is true. I had to change my wireless router's channel a few times before it would work with my wife's laptop (we're in an apartment surrounded by other residents' routers).
But I doubt that would only cause problems with games. If you're having channel problems, it should affect all network use - not just games. When I had channel conflicts, I couldn't even surf the web.