Ok looking at the partition layout there, you can do various things
The c: partition is self contained which is a good thing - the boot files are there so and it is the active partition so that any work with the other partitions will not effect the install
The bad news is that the partitions are in the wrong order for use with the built-in application - except for a non ideal result which I will explain.
Using the built in application you can right click on the two empty partitions and delete them. This will leave you space of 75GB that you can then right click and create a new partition and allocate a drive letter to, which will work from within windows and show as the c: and another, (D?), drive.
The issue with this is that it is not optimal to have the system partition at the end, (right side), of the drive.
If you wish to move the system partition to the start of the drive, (left side), you will need to use a 3rd party tool to delete the two empty partitions, move the system drive to the start of the drive, and then create the new partition at the end.
The tool I use is partition wizard ( the bootable disk version, as this makes things easier to move system partitions), which is free and has a good help section on the site with step by step tutorials for using the software
Partition Wizard is a Windows based FREE Partition Manager. It works as partition magic and supports Windows 2000/XP/2003/Vista/2008 server and Windows 7. FREE for Home and Business user.
Which method you use is of course your choice - the first method will work but the second is better if you later need to adjust sizes.