My xbox 360 won't connect to Internet
I have a regular xbox 360 and I don't have the money for the wireless networking adapter so I am using an Ethernet cable to connect and it worked before but all of a sudden it started connecting but saying that there were service alerts then now it won't connect at all it says the Ethernet cable is plugged in but when I test xbox connection it fails saying my Ethernet cable isn't plugged in I don't know what to do I really want to play on Xbox live please help
Here's what you can try.
With the cable attached to the Xbox, check your router to see if the corresponding LAN light is lit and flashing. Each LAN socket on your router should be numbered so you know which light to look for. If the light is lit and flashing, it means that there's connectivity between the Xbox and router, so your cable is probably fine. If the light isn't lit then you either have a broken cable or the LAN adapter in the Xbox has died. Try another cable (make sure it's a working one, try it with a computer first) and see if the problem re-occurs. If it does, then the LAN adapter in the Xbox has died. It's essentially trial and error to pinpoint the source of the problem.
If the router light is lit but the Xbox still can't connect, then you may want to consider resetting your router to its factory default settings. Obviously you'll need to configure it again.
What exactly were these "service alerts"? Did you get them on the Xbox or the PC? There's also a guide on Xbox support that you may want to go through.