You could install Ubuntu inst 12.04 or 13.04. But I recommend that you install Xubuntu 13.04.
Xubuntu is an elegant and easy-to-use operating system. Xubuntu comes
with Xfce, which is a stable, light and configurable desktop
Xubuntu is perfect for those who want the most out of their desktops,
laptops and netbooks with a modern look and enough features for
efficient, daily usage. It works well on older hardware too.Xubuntu
You can download the DVD Here Once downloaded you can burn the ISO to DVD, and boot from it, or create a bootable USB flash drive. To burn the DVD you can use ImgBurn, and for the USB you can use UNetbootin.