External WD USB 3.0 Drives - Windows 7 HP computer won't boot if they are plugged in


I recently bought two Western Digital My Book USB 3.0 drives, 4 TB in size.  They work fine but my HP computer running Windows 7 won’t boot if the drives are plugged in.  I have them connected to a USB 3.0 card that I installed in the system.

Any ideas?
I can boot the PC up fine and then plug the drives in once the computer is booted up.


  Pete / [Deleted]

Boot into the BIOS and make sure USB is after the HD.