Welcome to the TH Community, @mccombe_8!
Can you please provide more details about your system specs (PC configuration)? You should be able to install Windows onto the 3 TB HDD, but your motherboard needs to support UEFI for boot. Non-UEFI motherboards can only use larger than 2 TB HDDs as secondary/data drives. This is due to the fact that legacy BIOS uses
MBR (Master Boot Record) which can only support drives up to 2 TB in size. Whereas UEFI BIOS allows you to install the OS onto a larger
GPT (GUID Partition Table)- formatted HDDs. Another requirement for installing Windows OS onto a larger HDD is for the OS version to be 64-bit. You can check this Tom's Hardware tutorial on
How to Install Windows on 3TB/4TB or larger HDDs.
Let me know if you have any additional questions!
SuperSoph_WD