Delete a backup disk?

I have 2 questions..
Running Win7 Home Premium on a HP desktop, current with all Windows Update patches.

1. I have been using Windows Backup for a couple of years to back up this PC to a 1TB external HD. The HD contains a system image and several backups. I replaced the 1TB external HD with a USB3 2TB external HD on 1/2/2013, but did not delete the backup files on the old USB2 HD. The old HD is no longer connected, but I have it available. Windows Backup continues to "know" about the old HD and its contents even though it is no longer connected. How do I "delete" the old HD from Windows Backup's memory of it?

2. On the new HD, I have run Windows Backup 3 times, creating both the system image and the files backup, and letting Windows Backup manage the space rather than only keeping the most recent files backup. I ran the 1st backup when I installed the 2TB external HD. The 2nd backup ran automatically last night, and the 3rd backup I ran "manually", a few minutes ago. On the HD now is the system image and only 1 files backup that spans the date range from 1/2 until today. My question is - why were not 3 files backups saved on the HD rather than only the 1?

Blink,
After 3 backup runs as described by me in the 1st posting, only 1 item shows up when I display in Windows Backup/Manage Space on my new drive:
Backup Period Size
1/2/2013 to 1/7/2013 50.81GB
The "Manage Windows Backup disk space" screen shows:
Data file backup: 50.81GB
System image: 111.94GB
Other Files: 5.70GB
Free space: 1.65TB
Total size: 1.82TB

So, the above shows me that there is a single backup "Period", which I could delete using the "Manage Windows Backup disk space" window's "Delete" button (if I wanted to).
On the screen for "Restore Files (advanced)" screen I can select to "Choose a different date", and then it does display that there are indeed 3 backups included (1/2, 1/6, and 1/7), but of course I have no way to delete any of those 3 dates - and I assume I should not want to, right?

On my old 1TB USB2 external HD that I used for backup for a couple of years, I did notice that when I displayed the backups using Windows backup, many periods were displayed, and some times I had to delete 1 or more of them to free up space. I did not realize then that each Period backup file might have contained several incremental backups. It actually looked like a new Period backup was created each time that Windows Backup automatically ran (7PM every Sunday night).

I am surprised that Windows Backup does not have an option to clean up a backup drive of all its backups (even if it allows only 1 delete at a time), and when empty, remove that drive from being a Windows Backup drive. Seems like something is missing....is it?

Brink,

Just so I really understand - what I need to do is -
1. hook up my old HD so that I can delete each of its backups using Windows Backup application to delete the backups on that drive. After that I could reformat it if I choose.
2. hook up my new HD so that I can delete each of its backups using Windows Backup application to delete the backups on that drive.
3. reset Windows Backup back to its empty default.
4. use Windows Backup to define my new automatic backup schedule and create my 1st set of backups on my new HD.
5. let the automatic backups happen on their schedule each week

Correct?

Brink,
Before the reset and also prior to setting up Windows Backup again, should I delete the existing backups on the new HD (system image and the period 1/2-1/7)? Not really knowing exactly how Backup really works, I don't want to create a problem by leaving the old backup files on the new HD.

Brink
Thank you. Will post again after...