Among other useless things, I act as a shepherd of a public-use computer room at the retirement village. It is almost entirely based on Windows - XP, 7, and 8.1 "arriving". Also one iMac - hardly ever used.
What to do about XP?
My answer has been to install a Linux Mint 13 machine with "familiar" software:
Firefox browser, gmail/mymail/yahoomail/microsoftmail - all browser based, three flavors of solitaire. LibreOffice - a 100% clone of OpenOffice - which is on ALL the other PCs in that room. Google Earth, etc. Since it's a public use facility, I didn't install Thunderbird - though that's what I use on my own Linux Mint machine.
At least it is something to consider. There are printed versions of "Getting Started With OpenOffice" and "OpenOffice Writer" (text editor.) They are fully applicable to LibreOffice.
I have not received any comments and people have clearly used the system. The room's users are mostly canonical computer-illiterates.
I put icons for all of these applications on the desktop.