I am not an expert but here is my best answer:
Swap: Probably previous from the 'linux' word. It works as a supporting ram for linux
ext4: this is your linux
Unallocated: just empty space
Extended: I don't know!
ntfs: your windows is here
Can you maybe tell from the space of the drive? You can also mount the drive and look at the files inside. The C:\ drive will have files such as program files and Windows.
Mounting also gives you the ability to retrieve your files if you need some files. To mount the drive you just use Gparted, right click on the drive you want to mount and click "mount" (no magic, right? xD)
Otherwise you use the terminal. First, you can find the name of the drive using fdisk
fdisk -l
You will get a list of the installed drives, here is a list of mine:
Device Start End Sectors Size Type
/dev/sda1 40 409639 409600 200M EFI System
/dev/sda2 411648 1050623 638976 312M Microsoft basic data
/dev/sda3 1050624 206505983 205455360 98G Microsoft basic data
/dev/sda4 206505984 246810623 40304640 19.2G Linux swap
/dev/sda5 246810624 536717143 289906520 138.2G Apple HFS/HFS+
/dev/sda6 536717144 537986679 1269536 619.9M Apple boot
/dev/sda7 689291264 1456939007 767647744 366G Linux filesystem
/dev/sda8 1456939008 1465147391 8208384 3.9G Linux swap
/dev/sda9 537987072 689291263 151304192 72.2G Linux filesystem
The device name is /dev/sdx* (letter and number). For example, my EFI System device name is /dev/sda1
and so on. You can determine which drive is which from the device type column. It will be either NTFS or Microsoft basic data. I will mount my EFI as an example here from terminal
sudo mount /dev/sda1
You should see the drive mounted and be able to navigate through it. After you determine your windows drive you can then delete it. I hope this answered your question
Note: if you want to delete windows only because the boot is corrupted after installing linux then you might want to create another question with that problems. My experience with ask.ubuntu is that people here have creative solutions for every problem!