Yes, as long as you're sure that the disc has not been used.
Im 99.9% that it is unused. I contacted TigerDirect and asked them if it was normal to have a computer shipped with the OS already installed and they said yes it is common. However, im not sure if they installed at the factory before shipping to me, and if they did, why would they ship the OS for refurbished PC's to me if they installed it themselves? The Product ID on the label of my computer is completely different from the one that shwos up on my System Properties so im assuming it is unused.