GUID Partition Table, aka GPT, is the partition table, not the partition. The Windows default is Master Boot Record aka MBR. The reason you use GPT instead of MBR is because of the Logical Block Addressing (LBA) that each uses. MBR is 32bit and GPT is 64bit. This is the number of bits in the unique addresses of each logical block of memory on the disk and has nothing to do with 32 or 64 but CPU architecture. The short and small of it is that if you have a disk with a capacity of 2.2TB or more, you will have to use GPT in order to be able to address all of the memory blocks on that disk. This partion table is chosen when you initialise the disk and it does not alter when you create/delete/extend/shrink/format a partition or volume on that disk.
You do not need any third party software to create or delete partitions on your disk but if you intend to use your GPT disk as a boot disk for Windows, you may very well require a BIOS upgrade for your motherboard, as Windows bootloader looks for MBR disks to boot from.
In order to edit the partitions on your disk inside Windows 7:
Start Menu > riight-click "My Computer" > select "Manage" > select "Disk Management" from the tree in the left hand pane of the window that pops up, towards the bottom of the tree > select your 4TB disk from the list of disks there.
Your existing partitions will be represented as boxes along a horizontal bar. If you have an existing volume/partition crurrently taking up all of the free space on your 4TB disk then you will need to split this into the volumes you require, or you will have to delete it and create new ones to suit. The options to do such things are found by right clicking the partition box to wish to edit.
Under MBR you were limited to 4 logical volumes per disk but GPT does not have this limitation. I think it's 12 or something but that is just off the top of my head...