Solution

Ok now you should have taken apart your xbox 360 if your with me at this point you should just have the mother board of the console separate for all other components. the problem are the two stacks that are a bunch of metal plates spaced evenly from one another called heat sinks. These two heat sinks are attached to the CPU chip and processor with x clips and thermal paste makes sure of good transfer of excess heat. Your x clips should be fine as long as you didn't mangle them while disassembling, the real problem is the thermal paste on the three chips (two larger chips and a smaller one that have residue from the old paste on them). What you have to do is replace the thermal paste on these chips, you can find this paste at radio shack or another electronics store. If you just want a quick fix instead of going to get the paste you can carefully scrape of the old thermal paste and then as evenly as possible you spread it back over the three chips. In order for this to work you must run the Xbox 360 console with out the fan connected to overheat the console and basically re-adhere the heat sinks to the chips. If your not using new thermal paste then the problem has a chance to re occur but you can do the same steps again to fix again. I've done it about 6 times and it has worked every time for about 3-4 months except this last time where i bought new thermal paste and havent had a problem since.

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