http://www.theopendisc.com/aboutThose are what I'd use.
I think most of these Open Source programs are good to go on Windows 2000 and above.
Open Office, for example:
Microsoft Windows
Windows 2000 (Service Pack 2 or higher), Windows XP, Windows 2003, Windows Vista
256 Mbytes RAM (512 MB RAM recommended)
At least 650 Mbytes available disk space for a default install (including a JRE) via download.
After installation and deletion of temporary installation files, OpenOffice.org will use approximately 440 Mbytes disk space.
1024 x 768 or higher resolution with at least 256 colours
There are a couple of free programs I'd use in addition to the OpenDisc, especially on older, slower machines.
Those would be Irfanview, Abiword, and AVG or another active antivirus programs. Clamshell won't protect you if you do something foolish. An active anti-virus program will at least
try to protect you.
http://www.irfanview.com - a fast, lean graphics viewer/processor. Shrink jpegs, convert pngs, gifs, etc.
http://www.abisource.com - a lean word processor. On a slow machine you can open Abiword, do a quick edit, and save and close your document it in the time it would take for Open Office to simply start.
http://free.avg.com