AHHHHH!!! The Red Ring of Death! Fortunately there's a solution. This straightforward and incredibly helpful how to video will breathe some life into your XBox 360.
For this repair you also need
-Torx 8 Screwdriver/T8
-Torx 10 Screwdriver/T10
-A small flat screwdriver to open the back
This repair will work on almost all rrod's especially on the ones with 0102 0020 as secondary code. It CAN also fix the one red light in the right bottom with an error code on screen like "e74" but only if it's the GPU if it's the ANA or HANA chip it can't (unless you're lucky with overheating)
I already fixed 12 xbox 360's like this but you have to use heatpaste because all things like that will make the fix permanent. Otherwise it will not last long, same thing when you don't overheat. Of course you can put alternative heatsyncs under the memory chips and tricks like that but it isn't the SOURCE of the problem, however it can be good to do.
You can also do this without attaching the motherboard to the steel case, like explained. If you want to do that use screws with a flat top which doen't get smaller 10 mm long (without the top) don't put STEEL washers under the motherboard if you do this.