I can'tu nlock my MacBook Pro model number A1286
I went to work on an answer for you. I had to go through the steps myself rather than trusting my memory. The problem is that he software on the install disc did something to my drive so my Mac wouldn't boot*. So this is a bit more complex than I thought it would be. Here's the deal: prior to OS X version 10.7 Lion, it's a simple matter of starting your machine with the DVD called Mac OS X Install DVD.
***But WARNING:** If you have 10.7 or later installed on your Mac, resetting the password using the 10.6 Snow Leopard DVD may damage the directory or volume structure of your hard drive. This is damage to the data stored magnetically on the drive, not actual damage to the computer. Check your OS X version by clicking the Apple menu (upper left) and clicking "About This Mac" in the menu that drops down.
If you're not sure what version of OS X is installed on your machine, I'd suggest taking it to an Apple Store near you. Hopefully, there is an Apple Store near you. Before you go, sign up for an appointment with a "Genius" at your local Apple Store. Search Google for "sign up Genius Apple Store" or go to apple.com.retail/geniusbar
* I fixed my hard drive with DiskWarrior. Expensive, but highly recommended drive repair software.
Steps to reset password (ONLY for machines running 10.6 or earlier):
If you still have your system disks that came with your Mac, this will be pretty straightforward. Note: I go into detail because I don't know what you know. I'm not trying to insult your intelligence. :)
1) Slide the first system disc, the "Mac OS X Install Disc, gently into your disc slot (careful there isn't disc in there already).
2) Turn on Mac while holding down C key. Keep holding C key at least 30 seconds.
3) The first screen has you select your language. Click the arrow in blue circle to continue.4) The next screen it stops at says "Install Mac OS X" at top. **Do not** click the Continue button.
5) Instead, click the "Utilities" menu at very top of screen.
6) In the menu that drops down, click "Reset Password..."
7) In this, the last screen, Click your Mac's hard drive at top (hint: it's **not** the one that looks like a CD).
8) Under "Select the user account" make sure it says your main account. If not click to select your user name on the machine.
9) Under "Enter a new password for this user" click in the white and type a new password. It should be at least 9 characters long and contain at least one capital letter somewhere in it, and it should include a number somewhere, such as your lucky number. Something that's not too difficult to type. Enter the new password again in the box below that.
10) Click the "Save" button. Wait until it's done!! Turn off your Mac by holding down the power button until it turns off.
11) Turn on your Mac as you would normally. Type in your shiny new password when asked.
Critical: Write down password and put it in your nightstand or something. Memorize it. You'll need to know it. (Note: this is *not* the same as your AppleID password if you have one.)
Good Luck! I hope this helps.