Happen to be talking with an MSWindows admin about disaster recovery. He was talking about how it was a challenge to do recovery. I made a bet that I could have network of computers running in no time and not even use a single hard drive. I would need one cdrom though. Of course I was told it could not be done. You can guess what happened next with the wallets.
Anyway, we went around and made sure that all the machines would pxeboot except the system with the cdrom drive. I booted a Knoppix linux cdrom which has a built in terminal server. Once the machine was up, I made a few quick settings for the terminal server. We started booting all the machines. low and behold after a bit all the other machines were up and you could use all the software.
To make a long story short, the admin was dumbfounded and became an instant new devotee of linux.
See how you can at: http://www.instructables.com/id/No-hard-drive-network/ or http://www.instructables.com/id/Another-almost-free-computers-thin-client-set-up/ .
To convert a Rasperry Pi to an LTSP thin client see: http://www.instructables.com/id/Raspberry-Pi-Jack-of-all-trades/#step7
Step 1: What's needed.
An old pc that has a built in network card that supports pxe (pre execution environment) boot.
Network for the sort of thin client to connect to the server.
Server that supports pxeboot to push an os such as LTSP, DRBD, Redhat, or maybe MSXP Embedded remote boot.
Screwdriver for removing parts.
Certain old pc's where the bios does not support pxe boot can be made to emulate pxe with software via a boot disk using standard nics. (www.etherboot.org and www.rom-o-matic.org )
Free terminal server software.
linux terminal server
Update: I have even used old Apple Mac g3's via netboot as thin clients for LTSP 4.x. Weird seeing old ppc based macs boot from and Intel based machine. Of course you are loading Apple software and not Intel software into the Apple based thin client. There is even software to use the old Sun (now Oracle) thin clients with LTSP, but I never tried it.