If the OAPs have older machines then Linux would probably run quite well on them. I upgraded my father to Linux from Window 2000 (!) a few years back. He wanted to stick with Windows until I told him what a retail copy would set him back. I can fix most of his problems remotely, even to the point of getting his scanner working, when I told him to leave something on it so I could have something visible to scan and check the resulting file.
If it's a bit of email, web surfing and occasional letter writing, Linux is cheaper and easier, especially on older hardware as used for XP. It's bleeding-edge new hardware without drivers that lets it down, and that's the manufacturers' fault for not making them available, despite providing several flavours of Windows driver. Strangely enough, Windows sometimes has the opposite problem, new OS doesn't have drivers for older hardware because the manufacturer didn't bother to write one.