I suspect that others on the forum, like myself, are reluctant to give you an answer because attempting to delete the partition might render your computer unusable. It also might work just fine. With a bootable partitoning tool you could probably delete the Windows 8 install partition, move partitions around as needed to get the free space next to the c: partition and then increase the size of the c: partition to utilize the additional space.

I suggest that you first make a full image of the entire hard drive on an external storage device like a USB hard drive. Then you can experiment with the partitions.