[Solved] Adding a second SATA hard drive

If you follow sub mesa's suggestion you probably will see this new device in the lower right pane of Disk Management. It will show as a piece of hardware with only Unallocated Space and no letter name.

ANY new hard drive needs two operations done on it to prepare it for use by Windows. Until that's done, Windows will not see it in My Computer. They are Partition and Format. Windows Disk Management has the tools for this, but even easier are free utility software you can download from your HDD's manufacturer's website. Go there and find / download / install their tools for preparing and installing your new hard drive.

If you want to do this yourself with Disk Management tools, here's the sequence. RIGHT-click on the new drive in the lower right pane and choose to Create Partition. I assume two things: (1) you want to use ALL of this drive in one big piece, not break it up into smaller Partitions; and, (2) this is a data storage only drive, not to be used for booting from. If you actually want more than one Partition, you just make the first one less than the full size and come back later to this same place to create a second (or more) Partitions in the remaining Unallocated Space. But using those assumptions, you will be creating a Primary Partition, it will be non bootable, and you will set its size to use all available space. You run this and the first part of the job is done, writing to the start of the drive a bit of info in the Partition Table. When it's done, you RIGHT-click again on this new Partition you've made and choose to Format it. Format creates the file tracking system so Windows can use the disk. For modern hard drives, choose the NTFS file System unless you particularly need FAT32. Choose Quick Format to get the job done in less than 15 minutes. A Full Format choice does the Quick version first and then runs an extensive test of ALL the drive which takes MANY hours. When you're done, back out of disk Manager and reboot. You will find your drive in My Computer now. Note: some versions of Disk Manager include a Wizard that helps you set up BOTH of these steps in one operation, and that's handy.