You can run Linux from just a Thumb drive without even installing.
Here is what you will need
Thumb Drive normally I use 8gb or better since I buy them in bulk.
Linux Live - this will set up your thumb drive as bootable
http://www.linuxliveusb.com/
Pick the Linux Distro you wish to use.
Linux Lite- Overall a good Distro for beginners but by far not the only one, I install this one often because of all the included packages and speed.
https://www.linuxliteos.com/
Peppermint - Lite weight easy to run Distro
http://peppermintos.com/
Zorin - A great OS although the really good versions are paid
http://zorin-os.com/free.html
Lubuntu - A lite wieght version of Ubuntu 14.04, Very good and not entirely hard to figure out.
http://lubuntu.net/
1. Download and install Linux Live
2. Pick the OS you want and Download
3. Run Linux lite, pick the OS and let LL set it up.
4. Reboot PC and pick the option you want, Run in Persistent Live mode "No Install", Dual boot with windows or install over windows. The Distos will partition for you no need to do that yourself.