Problems shutting down and starting up

Question

my MacBook Pro (OSX 10.9.3) doesn't shut down when I want it to but goes into a coma periodically.
when I use "Shut Down" every once in a while via Apple menu, the machine doesn't appear to actually shut down. when I open it or got to it the next time, it's in a state of sleep and I can't awaken. when I finally get it to shut down manually and restart, a dialogue saying "you shut down due to a problem" arises next startup. this whole chain is odd to me. I'm a long-time Mac user (IIvx, iMac and iBook) and I don't recall the startup problems but maybe I've just forgotten.
moreover, and related, sometimes when I simply shut the screen to put MacBook Pro to sleep, it won't reawaken. clicking space bar or pushing mouse pad have no effect. so then I have to manually shut down by holding power button, and then restart.
in the old days, we would "zap the PRAM" when there were freezing or startup problems. (I don't even remember how to do that, as my iBook which I had for ten years never gave me these problems). do I zap the PRAM? how? any other ideas?
Thank you!

Answer 1

brutus775,
if you boot into Safe mode, does your MacBook Pro still go into periodic comas?
With MacBook Pros, one “zaps the NVRAM” (or “resets the SMC”) instead.