What colour is the light on the power supply? If it's green, the PSU is fine, if it's yellow/orange, your friend is right.
It is over heating. What is the longest you've left it off for? Leave it off for a day or two. Once it has cooled down for a day, run it in front of a fan, nothing too strong because REALLY cold x hot silicon is a great way to crack it. Unless you're still under the 3 year extended warranty for e74, in which case, do whatever you can to force a hardware failure w/o tampering with the inside.
my shit use to be green, now that shit orange bro on the power suppy
i been having it off for a week now,but like you said i feel like its the power supply