Fixing the XBox 360 - Repairing the 3 Red Lights on Your XBox
So what do you do when this happens to your XBox? First of all, don't panic. In nearly all cases, your XBox can be fixed and the 3 red lights error will go away. Before doing anything, try these simple solutions first:
After you’ve let it cooled, plug it back in and see if the 3 red lights have disappeared. If they haven't, now you need to consider what to do next. If your XBox is still under warranty, it is easy enough to return it for a repair or replacement -- however you need to keep in mind that if you send it in to the Warranty center, you probably won't have it back for at least two months.
The other alternative is to fix it yourself. There are a couple of different XBox repair guides available for the XBox designed to get rid of the 3 red rings and following the instructions is pretty simple and this is the best way to go if your XBox is either out of warranty or you do not have the patience to wait two months.
I fixed my XBox myself while it was still under warranty because I didn't have the patience to wait and since then haven't had any problems, but it's up to you whether you want to do that. If it's under warranty, you void the warranty when you open the machine up. However -- the red lights repair is very easy and since this is usually the main thing that goes wrong with the XBox, it's usually worth doing. Also, some of the available solutions don’t even involve opening up your Xbox, so if one of those works for you, you're all set with your warranty protection.
To fix your own XBox 360, be sure to check out the XBox 3 Red Lights Repair Guide.