Firstly you may be in luck and not be suffering from the red ring of death; if your Xbox only displays 1 red light then it means you are having a general hardware failure. This isn't all that major and it can generally be fixed by disconnecting and reconnecting the cables or Removing and re-inserting the hard drive, contact Microsoft customer support if the problem persists. 2 red lights on your button indicate that the system is beginning to overheat, if you see this warning then immediately turn the console off and let it cool down before resuming play, also try keep it in a well ventilated area for future use. If your AV plug is loose, then your XBox 360 will show 4 red lights, this is a simple problem and it can be easily fixed by plugging the cord back in its place.
You can send you console back to Microsoft and have them fix it. This is an easy process however it can be a lengthy one, as it could take upto 8 weeks to get your console back. Also you will most probably receive a different refurbished console which could encounter the same problem in the future. As I mentioned earlier some gamers have been through as many as 4 consoles only to see their fifth console become doomed again.