I want to partition a 5 TB HD that is fairly new & has probably 200Gb of pictures and documents on it now. Can I split that HD up into 3 different partitions without removing everything that is currently on it?
Sure you can, go into disk management right click on the drive you want to partition and click on shrink drive.
To get in to disk management
click on the start button in lower left or in the (search for anything box) and type Computer Management
on the left had side expand the Storage tab if its not already and then click on Disk Management
Once the drives populate just right click on the drive you want and tell it to shrink volume, once shrunk you will get a black box on the drive that says unallocated, right click on it and tell it to become a new simple volume. this will take you through the steps of making it a drive and giving it a drive letter. if you want to split that then just right click and tell it to shrink the volume again.