Use Gparted to remove windows partition and consolidate partitions

Firstly, a disclaimer, as I can't exactly reproduce the steps to walk you through, this is just what I would try if I backed up all my important info first.

Here is a comparison of my partition table:

I have a 500GB hard drive which is the ext4 filesystem and the fat32 EFI is used for the bootloader. So, you could delete the ext4 fs associated with your Windows install (is that the one mounted at /media/ ?)

So it looks like you want to KEEP:

• fat32 EFI filesystem (that's the bootloader)
• ext4 linux storage filesystem ( presumably the 200GB partition ??, please double check)
• the linux-swap, which isn't absolutely necessary but helps free memory on low RAM systems

Everything else can be selected then Partition > unmount and Partition > Delete. Once you have ~700GB of unallocated storage you can select ext4 and then click Partition > resize/move and extend the drive to fill the unallocated storage. Finalize the procedures, clicking the green tick, and you should be set.