As you may have heard I've problems with the online connection on my 360.
Whereas before I sent it to repairs (for faulty USB ports and not a RRoD, to boot! Only reason I use those is because of my arcade stick), I could play online and it would be fun and all that jazz, now everything works except online. It detects the network, but it cannot connect. After restarting the router and the modem six times each (and everything else connecting except the 360, obviously), I pretty much called Xbox support and lo and behold, they think the wireless doohickey is broken (granted, the sheer fact that you have to buy a wireless doohickey in these times is complete crap but I digress). After barely two tests (and them being a repeat of each other), they figure that it's the doohickey that's broken.
Seriously I'd love to know how they arrived to that conclusion so fast when it was working just fine before I sent my console in for repair. What? Was it scheduled to explode as soon as it got hooked to a refurbished 360?