You have a Thinkpad? As far as i have heard their linux compatibility is fairly good. An yes, ubuntu won't have more problems than windows with low power devices. My old 4GB ram, 1.4GHz 4 core laptop ran linux mint fine.
Ps: linux mint is a ubuntu fork, and has a desktop interface that looks a lot like windows (example: in the bottom left there is the linux mint logo that you can click to open the start menu like on win 7).
Make sure to read the man page before so you don't remove the runtime functions