My MBP shuts down randomly

[Gaogier]

Hello

Macbook Pro mid 2009
2.53 GHz Intel Core 2 Duo
4 GB 1067 MHz DDR3
OS 10.8.5

Randomly my macbook pro will shut down, I have replaced the battery which was in need of doing, first time ever.

It won't reboot, for hours to minutes to seconds to days it will randomly reboot back to normal - able to post this as normal.

It could "crash" any time, as soon as I boot it up, to watching youtube videos for hours and hours with no sign of "crashing" then bang it may "crash" here or there…

Any ideas why or how to fix?

 

[keysofanxiety]

Could be graphics to be honest, the NVIDIAs had a bitterly high failure rate. If that was the problem, it would cause issues synonymous with what you're experiencing.

Other less likely issues could be RAM or even OS, as Mountain Lion is pretty out of date and no longer patched. If you can, fit a cheap SSD (60-120GB) and throw on El Cap to see if the problems persist.

 

[Gaogier]

How can I tell if its the Graphics card, RAM or OS?

 

[Mr. Bean]

You have a similar problem to one of my MBPs. I suspect this is a GPU issue. There was a time when Apple issued a recall where you could bring it in to have the GPU replaced. I guess they've figured out that it was a GPU problem. Why don't you look up the list of Apple free repair programs in the past to see if your model (based on serial number) falls under any category. That might help narrow it down to what the potential problem might be. If memory serves, I think the 2009 model did not have widespread issues so there was no such program. I could be wrong though.

Edit: I've just checked and it looks like there was no such program for your model.
http://www.apple.com/support/exchange_repair/

Initially I was thinking of this
http://www.apple.com/support/macbookpro-videoissues/