Can't say I blame him, though. I'd go here for answers to homework if I didn't have enough real problems as is.
Just to repeat and emphasize what was already said, computers need an operating system to do any real function. Now, this is not to say it will do nothing at all without an OS. I found that out trying to install XP OEM.
If you don't have an OS, the computer will get past the diagnostic screen, meaning it will recognize disks, memory, etc. but you'll get an error message before anything else happens. It needs to recognize the drives to install Windows/Linux/whatever in the first place, but you can't run programs, navigate drives, that kind of thing.