ps3 shuts off by itself after loading game

Hey guys need your help. Got a fat ps3 80gb. Weird that one morning i wanted to play then all of a sudden this happens. Last time i used it was a month ago before this happened. If you guys know how to fix this or at least tell me the cause and what i can do, please comment down below.
fyi i tried playing with all my games after i loaded 2k thought maybe it was the CD. Now i tried playing RDR, gta, dead space and same result happened which NEVER happened before.
first i assumed it was YLOD since the light pattern went Green yellow then blink red but then i still get to turn it on and remove the game and stay on the ps3 menu for a long time. Then i assumed its hardware problems maybe the thermal paste or the chips are loose idk not an expert at this so please anyone who can help, comment down below. Thanks :)