My answer is based on the hardware of a netbook MSI U135.
You must use a 32 bit Linux distro, I suggest a lightweight Ubuntu derivative.
- Linux Lubuntu is a great alternative to Ubuntu for PC with very low resources or with very resource consuming tasks, I use it on my EeePC; this distribution uses Pcmanfm and Openbox, two light graphical applications to manage your desktop (which is LXDE).
- If you need more default "desktop"/user-friendly functionalities then use Xubuntu (that features, of course, xfce).
Please, follow the Official Ubuntu installation guide to install any of the Ubuntu derivatives or Ubuntu itself. Follow the specific distribution site to find a specialized community for any of your doubts.
Remember to update your system (at least do the security updates) after a fresh install of any Linux/*nix distribution.
Use the "LTS" version only if you want to install a new system on a production machine, because these versions aren't updated very frequently and may have different versions of the kernel.
Please, feel free to comment down here if you need more help.
Have a nice experience.