Hi gja,
first of all: WELCOME TO THE DISCUSSIONS!
Most disk sets sold on eBay or similar sites are hardware specific software install disks. You
CANNOT use hardware specific software install&restore disks that shipped with another computer. These simply do not contain the hardware drivers for any other computer model but the one they originally shipped with. You have to buy the retail full install DVD.
Besides this technical limitation it would also be
ILLEGAL (unless you can guarantee and prove that the original owener completely erased it from his computer). Apple's
Software License Agreement states in point 2:
2. Permitted License Uses and Restrictions. A. This License allows you to install and use one copy of the Apple Software on a single Apple-labeled computer at a time. This License does not allow the Apple Software to exist on more than one computer at a time,...