diagnostic

I have here a MacBook Pro 15" A1286 EMC 2535 that is showing strange symptoms : works like a charm and could be fully reinstalled, but sometimes shuts down abruptly after a few minutes. memtest86+ run from Gparted live CD fails with any RAM stick, whatever the brand (Samsung, Hynix, ...), the...

I find that I don't use the event viewer a ton. I think it's a blind spot, perhaps. I generally don't use many windows built in tools, and go to third party tools. Do any of you rely on it on a regular basis? What are some issues you gents and ladies run into, where EV can reliably help...