According to http://www.via.com.tw/en/products/processors/c7/specs.jsp, most distributions should work. This applies to the ssd quesion as well (any up to date distribution should be fine).
Relatively lightweight installs include http://crunchbanglinux.org/, debian based so if you are new to linux, its easier. This one also only installs openbox as your window manager, no desktop environment. Openbox is highly configurable and pretty stable.
There's also http://lubuntu.net/, which uses the LXDE desktop environment and Openbox as its window manager. It's really just Ubuntu without GNOME/Unity. LXDE emphasizes on lightweightedness.
Of course, with linux there's always more ways to do it, but if you want a ready to use, relatively lightweight system, the above are pretty good choices, both should have a word processor pre-installed.
Personally, I use arch linux. But it's not for new users and can take some time to install and configure (the amount of configuration that can be done is seemingly endless), especially if you don't know exactly what kind of system you want beforehand. The arch linux wiki, http://wiki.archlinux.org/, is a good place to learn anything about linux installation and configuration.