I checked the website for chipset infos.
Onboard graphics: Intel GMA -> No driver on the internetz
Onboard sound: Chipset cannot be identified, but by the W2K-driver, it seems there is no driver for w9x as well.
Using W9x-compatible add-in cards (i.e. a PCIe card for graphics and a PCI card for sound) is technically possible, but not advised, as by the build of that small box, even low-performance GPUs will heat up considerably, as there is not even a remote chance of ventilation.
If you want a supported OS for that hardware, I'd suggest either Windows 7 32bit (you may have a license-sticker on it), otherwise any flavour of linux will provide a basically secure-enough system. With that machine, anything beyond office and surfing is...