now I have 1 red light

hello i have a xbox 360 i have add this for about 6 to 7 years now - about 4 years ago i add the rrod sent of for the fix kits and it worked good - now i tryed to update my software to lt3 now i get the rrod again - so i striped it again changed the thermal past that did not work then i tryed the heat gun - geting ther lol now i have 1 red light - tryed resoldering the joints on the tv connection that did not work - still trying though before i dont know lol