This disease recently happened to my PS3. I tried to turn it on and the light went from green too yellow after beeping twice and it wont work. Has anyone ever heard of this or know what to do? I googled it and found this video. http://www.youtube.com/watch?v=Tu0k4d76S5M
It's a lot of trouble to fix on your own. Their are guides that you can google for but honestly I would just send it back to Sony and pay them $150. Unless you happen to be able to reball the gpu/cpu whatever is messed up.
Their are third party places to fix it for cheaper than 150 I paid this site $60 and it was fixed. http://www.ps-pros.com/(X(1)S(qof4f445aiqthx555ugqta45))/playstation-repairs.aspx Its cheaper and faster if you go there. In Long Island i believe.
Do these guys actually reball the systems to fix them or do they just do a reflow? If they just do a reflow it's likely that the problem will come back again. It also says that the average order is $99. If it is a reball and $60 dollars and it's close by it wouldn't hurt to try.
I dont know what was wrong with my PS3 "fatty". But they fixed it for 60. And i didnt lose any game data. Sent a friend there too. Quick and cheaper.