getting a macbook pro up and running - where / how do I get the OS, where to get a cheap power supply?

I helped a friend out who's dog supposedly peed on their child's macbook pro 13.3.  I'm a windows person / don't know much of Mac things.

The child was saying it didn't boot up but there were things on the hard drive they wanted.  I took out the hard drive and got the data off and copied it to the new mac they got.  They let me keep the old machine - i figured for parts / sell on ebay.  I gave them the old hard drive as a 'backup' of the child's files as of the peeing incident

That was a few months ago.  I never noticed an odor or wetness when in the laptop (it was a couple weeks after the supposed peeing that I got the machine).

I've had the machine sitting around and still no odor.  I finally went to list it, for parts (I didn't have a power supply for it and on its own, it didn't POST - either 'cause the battery was dead or the pee blew things up inside... and there's no hard drive).  The keyboard keys all work fine - none stick or bind as I might expect from a liquid being poured in it.

I realized if I could power it up I could describe that better and maybe get a better price.  I borrowed a friend's mac charger and this thing fired right up!  I happened to have a hard drive from a different mac - I helped another friend move to an SSD and I had their old platter drive hanging around.  I put that one in and the machine booted up. I went into the guest account, it rebooted and I got on the web (the wifi card, touchpad, keyboard, speaker, display all seem to work).

So I want to wipe this hard drive and install a clean OSX version.  Anyone have a recommendation on the steps to do that? I guess I could google that but want to get the steps for a mac dummy : )  From what I can tell, it's a A1278 13.3" Laptop, i5 2.5GHz processor,  4GB RAM and the model numbers? are A1278 and  MD101LL/A.  Is there a certain version of OSX you'd recommend for this machine?  How are the specs?  I saw that there's 2 - 2GB RAM sticks in there.  Can I / would I want to take those out and put in more RAM?

And the power supply - are their 3rd party / aftermarket power supplies that work and are reliable? Or is the magnet power connector patented and only apple makes them?
Who is Participating?
Davis McCarnConnect With a Mentor OwnerCommented:
Genuine Apple AC Adapter (don't buy a knock off!) $22:

Most newer Mac's have a recovery partition so you can reinstall the OS without any discs.  Here is one way to do it:
Gerwin Jansen, EE MVEConnect With a Mentor Topic Advisor Commented:
You have a 'free' MacBook - just buy an Apple adapter.
BeGentleWithMe-INeedHelpAuthor Commented:
That link for the power supply is a 60w. The one that I borrowed from a friend is 85 W 60 is enough?

 And I didn't get to see the video yet but the hard drive that's in there now is from another Mac. Are there issues with The recovery partition and licensing /serial numbers from the hard drive not matching the license/serial numbers of the actual machine the hard drive is in?
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strungConnect With a Mentor Commented:
That sounds like a mid 2012 MBP. I agree. Just buy an Apple adapter.

To wipe and re-install, boot into the recovery partition by booting while holding down command-r.

Go to the Utilities menu, select Disk Utility, click on "Macintosh HD" in the upper left and select Erase. Set the format to Apple Extended Format (Journalled).

Once you have erased, back out of the utilities menu and select the option to install an operating system.
Davis McCarnConnect With a Mentor OwnerCommented:
The 60 watt adapter is what your MacBook calls for so you don't need the 85 watt.
There is another method for reinstalling OS X; but it would need you to know the administrator password and your mac must be close enough or it wouldn't let you login as Guest.  Try the steps in the video.
serialbandConnect With a Mentor Commented:
Assuming you have the correct model, you can upgrade your RAM to a maximum of 16 GB.  It should still work with only 4 GB, but you won't be able to open too many programs at the same time and you should remember to quit them, not just close the window when you switch.

The dog pee probably dried up enough that it's not shorting out any circuits and it can boot.  Still disgusting.  Assuming it's all working fine and it's the correct model, option command r will let you install the OS from the internet and let you install the factory installed OS.  You can then upgrade OS X from the Apple Store, or if you have a copy of any intermediate Apple OS.  Without the option key, it will try to boot from the local recovery partition, and that won't work if you have no partitions yet.

The 13" MacBook Pro comes with 60 Watt Apple adapters.  The 15" Macbook Pro needs a 85 Watt adapter if you're maxing out processes and charging the batteries at the same time.  You can run a maxing out a 15" on a 60 Watt adapter, it will just stop charging and go into power only mode.  If your battery is fully charged, a 60 Watt adapter will work fine with a 15" quad core.  If you're not running much, it will just charge up slower than with the 85 Watt adapter.  You can even use a 45 Watt Macbook Air adapter on a 15" quad core Macbook Pro, but you can still expect the battery to drain if you're running stuff.  If it's turned off or in sleep mode, any size adapter will charge the batteries of any sized MacBook from empty to full.  Only do this with genuine Apple Chargers.  The smaller units will get hotter than normal when used on the larger laptops, so I don't suggest using them on the larger units long term.  You can always buy the larger units for any of the laptops, if you prefer, but it's not necessary.
Kyle SantosConnect With a Mentor Customer RelationsCommented:
I definitely recommend adding RAM and putting in SSD.
David AndersConnect With a Mentor Technician Commented:
Everymac lists complete specs
A1278 is the case model.  
This is your macbook pro model  [13" Mid 2012 Macbook Pro]
About This Mac under Apple Menu is the model information.
You can see used prices at
They sell power supplies, new and used.

Etrecheck is a good diagnostic
Google "OSX version"
8Gb would be adequate
BeGentleWithMe-INeedHelpAuthor Commented:
Thanks for all the help guys! I did a mix of the video above (press Command S at startup), a video that followed after that one (Option) and strung's Command R.

I don't think it had the recovery partition - I didn't see that at any point. but in disk utils, I erased the drive, then went to restore the OS and I think it downloaded all of it!?

>>> Where's the disk utility stored? in a partition in the hard drive? on the mobo? I was afraid erasing the disk would leave me without disk utils.

And it installed lion - osx 10.7  I updated software and it's installing a bunch of things, (it rebooted and now says 10.7.5)  but do I want to move to newer versions of osx?  I do that in the app store, right? I have to log in with an apple ID? That won't stay on the computer once I log out?

OH!  1 last question - one of the rubber 'feet' is missing.  any chance there's a place to get that?
Gerwin Jansen, EE MVETopic Advisor Commented:
BeGentleWithMe-INeedHelpAuthor Commented:
Thanks.  That was a kinda lame question.  sorry!  

Looking on ebay though, I'm intrigiued by how many are selling just the outer part of the foot, but not the inner.  But I overthink things too often : (
If it still doesn't have a recovery partition, re-downloading the OS to the hard drive and re-installing will automatically create a recovery partition.
Davis McCarnOwnerCommented:
Replace the outer foot.  Nobody will ever know the inner "plug" is missing.
BeGentleWithMe-INeedHelpAuthor Commented:
Outer foot only?  I thought they lock / glue together / more durable than just outer which is like a band aid / sits on surface only
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