Revert to Factory Settings from MBP install disc

I just recently purchased a new MBP 15inch... I am trying to give my old Macbook to one of my family members but I would like to return it to its factory settings before handing it over.

Unfortunately I no longer have the install disc I used to upgrade to leopard from tiger. Can i use the install disc that came with my new MBP. I noticed it specifically says "15-inch MacBook Pro Mac OSX Install DVD"... Will this be a problem or is there possibly another solution?

The disk for your new machine will not work on the old one. Original disks are machine specific.

If you're "giving" it to them, have them spring for the new Snow Leopard Box Set. $170 for latest OS, plus iLife and iWork '09. It's a bargain.

Or find your Leopard disk.

Or create a new admin user for them and delete your user from inside that new account.

Thanks for the suggestions. I thought that would be the case.

If I create a new admin and erase my old accounts will that remove my applications and files?
I have about 25gb worth of apps on only a 80 gb hard drive and I know they are not all needed.

Most applications are not stored in the user account, they're stored in the Applications folder in the root. Only the preferences are stored in each user account.

You will need to delete any apps that remain as you feel appropriate.

Well, bobtomay is right, that your apps will still be there. However, unless I am mistaken, your FILES will be gone with your user account. Whatever was in your home folder will probably be deleted, as long as you delete the home folder with it.