GParted is a free partition editor for graphically managing your disk partitions. With GParted you can resize, copy, and move partitions without data loss, enabling you to: Grow or shrink your C: drive, Create space for new operating systems and attempt data rescue from lost partitions. GParted is very similar to “Partition Magic” a commercial program from the late 20th century.

You could go the GParted website and download the ISO linked to on that site but the best idea is to get a Linux like Linux Mint or Ubuntu and launch GParted while running the live CD.