Do I need to provide an operating system when selling a pc?

[Will3214]

Hi, a friend of mine and I are going to sell a pc on ebay that we built, and we are wondering if we need to include an operating system. We are only selling the pc, not the monitor. I see a lot of people that are selling pcs that have an operating system included, and they aren't selling a monitor either. How did they do this, did they just buy the copy of the operating system and include the code with the pc? Also, if we don't need an operating system, what do we need to set up on BIOS before we sell it? Sorry for all the questions, we are very new to this. Thanks!

 

[WyomingKnott]

You can sell a PC without an OS. People will pay less for it than one with an OS already installed.
This will almost certainly not be a profitable enterprise, though.