A barebone computer is for those computers with Mainboard or CPU problem which are out of date or can't be replaced with its own kind, and even upgrading your old computer or redesign it into a new and fast sytem. barebone computer is partially-assembled platform or an unassembled kit that can consist of any combination of: case, power supply, Motherboard, CPU, Memory, video card. Barebone computers are available in nearly any form factor. Assembling a barebone computer by hand is usually less expensive than buying a pre-configured computer. Barebones systems sometimes include a CPU or RAM but rarely any mass storage media (hard drives) or Operating System.