When you Install Win 7 in a machine, it automatically looks around for a second HDD. If it finds one, it places some semi-hidden backup files on it as part of the Install. The intent is that at some later time, if the boot disk has problems booting because of corrupted system files, it will automatically go to the hidden backups and restore from them, then complete the boot. A nice feature. BUT people have found that, with this system functioning, that second drive with the hidden files MUST be in your machine ALWAYS, or it won't boot! So you cannot remove that drive later.
Some people dislike this feature and defeat it. Just do NOT connect any HDD other than the first one when you install Win 7. In this configuration, Win 7 will put those semi-hidden backup files on that same HDD (not quite as safe as on a different drive). AFTER you have Win 7 running, you shut down and install the second HDD, then reboot. Win 7 will find it. In your case, the drive is already Partitioned and Formatted, so Win 7 probably will let you use it right away. You do NOT have to wipe it out, etc. BEFORE installing it in the new machine.
Now, since you actually do want to wipe the old drive and start fresh, I suggest you simply use Disk Management in Windows in the new machine for the task. Locate the unit in the BOTTOM RIGHT panel of Disk Management (it SCROLLS) and RIGHT-click on its existing Partition(s) and Delete it (them). It will become all Unallocated Space. Then RIGHT-click on that space and choose to Create and Format a new Partition. I assume you'll want to make it the entire drive, and use the NTFS File System. I'd suggest doing a Full Format if it offers you a choice. That takes many hours, so just be patient and do something else. When done, reboot the machine to ensure the Registry is updated and your drive shows up properly.