I got free RROD Xbox 360 from a friend and I fixed it by reflowing motherboard with heat gun.

I didn't want that Xbox would overheat anymore, so I added one fan to blow right to the gpu and one near the cpu. Only way to make fan to blow to the gpu was to remove the dvd-drive and put it to the roof with longer sata-cable. There is duct tape on front panel so that air wouldn't come out there.

It isn't pretty at all, but it is working and I'm happy with it. I also noticed when I was already playing with this that I could have put the cpu's extrafan inside the case, not outside like it is now.