So many people have this problem and don't bother to search for the answer... IT'S ALL OVER THE INTERWEBS PEOPLE!!!
You have 3 options:
1. If you have a warranty, send it in and get it repaired/replaced.
2. Buy a new Xbox 360
3. Fix it yourself.
If you pick the third option, then there are some steps you need to follow. But first, NEVER USE THE TOWEL/PENNY/ETC TRICK! EVER! That is the number 1 cause of irreparable Xboxs.
Ok then, now you need to check the error code of your Xbox. Because you have 3 rings, you have a general hardware error. To find out the specific problem, you have to find the code. To find the code, the ring should light up with 1-4 segments. If it's 4 lights, it's a 0. 1 means 1. 2=2. 3=3. Hold down the "Sync" button and press the eject button. Write down the first number. Still holding the sync button, press the eject button again. write down the second number. Find out the 3rd and 4th numbers the same way. After you have your 4 digit code, find it on this
list and see what your problem is. Now google how to fix your problem and follow the instructions. Remember, get the right tools and be patient.
As an example, my Xbox got an error code 0102. To fix this, you have to do the
x-clamp fix. I followed it carefully and to the letter, and now my xbox is up and running for just about $10.
EDIT: For the other people.
1 segment (Bottom right) is repairable in most cases.
2 segments means that it overheated. Turn it off, wait an hour or so, it'll work like new.
3 segments, like I said, is a general hardware failure and can mean quite a few things
4 segments means that your AV cable is unplugged. Plug it in.
