Hi,
Well, there are 2 ways:
1. Install that software which you want to install on C: partition to any other partition if you have.
2. Or really go for expanding your disk if that software doesn't support installation on another partition. You have to just go to computer management, just search for it in the start menu. It is a builtin tool to edit your partitions. After opening computer management, just expand to disk management section. Press tab key once or twice until you hear list with your screen reader. Press down arrow to navigate to your C: partition and press applications key or shift f10. Select the option to expand disk space to enter the wizard of expanding the partition size. The wizard will check the available free space on your disk and it will show you the available size in mb. Just type the amount of space which you want to increase in mb and let the settings be on default. Just press next a few times and yea! Your c: partition is expanded!
Ask me if you need more help on it.