Working on a friends MBP. Now I am no experts since I only had my RMBP for a year. But I told him I would take a look at it. My friend wanted em to reinstall the OS since he thinks the hard drive is the issue. This MBP will restart/reset for no reason at random times. In an effort to correct the problem the MBP was taken to the Gbar and they told him it had a third party hard drive and they would not work on it. So my friend asked me to re-install his software on a new hard drive (Since he has no OS disk). Well I got the PC re-imaged with a clean 10.9 load. NO Change, So I put back the original drive. Booted all is well and then a few hours later the PC restarts. MBP 17in. 2.66Ghz early 2009 8GB Crucial ROM MBP52.008E.B05 SMC 142f4 Next I tried and tried to get the AHT to work but after three days i just can't get it to work. So I downloaded MEMTEST from e-junkie.com and as soon as I ran that test the system restarted. So I reseated the memory sticks and retested. Results the same thing, Randomly the system will just restart. I need help isolating the cause, I don't think it's the hard drive. I'm thinking Memory. But it could be the motherboard. Also I noticed it runs supper hot, compared to my rMBP. Temperature Gauge App shows it got up to 212F. Advise please.