Go to Disk Management (search for it in the start menu's search bar, it'll show up as Create and format hard disk partitions) and reformat the drive as GPT. That should solve it. Keep in mind that you will lose all data currently on the drive, so back up anything important.
If the 4TB drive also has your OS on it things get complicated because you can't format the drive you're currently booting from. That's getting into the territory of booting a Parted Magic disk or something and doing it from there. If your OS is on this drive let me know and I'll write out the steps to get it done.
EDIT: This assumes you have at least Windows Vista (64-bit version and a UEFI capable motherboard if you're using the drive as a boot drive).