YLOD fix working more or less

*****FAT PS3****Followed a tutorial on youtube of a guy who did it, anyways, cleaned every crevice in there and replaced old thermal paste with new one (not Arctic Silver but the only thing they had in store which is a cheap chinese paste). Before I couldn't even use Netflix. Now after I assembled the thing back and plugged it. Ran smoothly with netflix for an hour(did that for warmup) Then I proceeded to insert a disc and try to play it but it died and the little red bugger started flashing again. Now it does run when I play downloaded games such as Infamous, question is why? Is it my blu ray unit that is overheating it? It only dies when I attempt to use a disc, doesn't die any other way. Btw the blu ray unit is located above the cpu and gpu which have the cheap paste on them.