Install the Universal USB Installer for Windows, and once installed, launch it. Choose the Ubuntu distribution you like, and have the app download it for you onto a USB flash drive. Then, reboot your PC, and choose to boot from the flashdrive. That will start the version of Linux you chose as a LiveUSB, which will be able to use data files (music, video, text, graphics) on your hard drive. When you know which version you like the best, then you can install it from the LiveUSB; if you chose to, you can resize the Windows partition, leaving Windows intact, and install Ubuntu alongside Windows.
There are many versions so I suggest you try several, and choose the version you like. There are differences in both the desktop environment as well as the apps and utilities they use; suggest you pick the desktop you like (Unity vs Classic GNOME vs KDE vs Xfce vs LXDE) and if there's a different app you find in one distro which you want in another (e.g., a different file manager), you can install it later. I prefer Xubuntu 13.10 right now on my Lenovo T500 but your mileage will vary.
Just like you can have both Windows 7 as well as Ubuntu on your machine, you can also add multiple versions of Linux, and choose what you want to run at boot.