I'm on Windows 7, got a new 2 TiB NON-external hard disk. When I plug it in it doesn't show up on the Disk Management list in the Computer Management window (that you get by right-clicking My Computer and selecting "Manage").
At first I thought it was broken, but I could see it using a friend's computer. I've run a full disk scan using the official tool from Western Digital, no problems.
I've formatted it and partitioned it at another friends place, I've even encrypted the disk fully without any problems, then mounted it and placed a text file on it with the word "hello" inside and saved the file.
When I boot my own computer the disk shows up in BIOS. So the disk is not broken.
I've tried changing what SATA slot on the motherboard I stick it in. Makes no difference.
After all this: Why won't my Windows 7 discover the disk???