I have done all the things you've said in the past to my xbox360 (the very first gen
version). The trick fixed the problem and lasted for 4 months...then it RROD again with
the same error code. Used the same trick, it lasted for less than 4 months, then 2
months, few weeks, and at the end few hours.
I found this guy who reballs xbox360 cpu at a very cheap price in Asia. He was nice enough to
show me how he reballed my cpu and gpu at his place. You can google or youtube to
see how it actually works. There are over a hundred solder balls under the CPU, and you
can see microsoft cheap out on the soldering, a bunch of the solder balls under my cpu
turned dull and stuck together.
I am not an electronic specialist, but this is what he told me...he said if you are lucky, the
solder will reflow again, but if you have some seriously "burned" solder dots (for example
a light bulb terminals, if it turns black from over voltage or over heat, then it will not be
conductive again, you can either replace the wire or the terminals) you will have to reball
that particular solder.
if I were you, I would sell it to somebody online asap, then get yourself a brand new xbox360,
add some new fans and enjoy the games