A:Answer It is assembled with windows installed. Components are good quality - the ones I bought had MSI and Asus main boards in them. They also used Phantek cases, eVGA power supplies, Geil ram, MSI RX580 OC Armor video cards. Great room to upgrade - all main boards had a M2 slot, could take up to 32gb ram. Cases have little 2.5" drive holders just inside the back cover for SSD... just really nice solid builds, I would buy again and recommend to others.