NovaBACKUP Business Essentials (B.E.) v19.3.x and newer (versions older than 19.3 did not contain a "Recover Previous" function in the Virtual Dashboard to utilize).
There is a "Recover Previous" (basically a way to import prior backups to list them) function to utilize for Virtual Dashboard (AVD) backups. If your system does not work anymore and you have to set up a new system with a fresh installed Windows and NBK B.E., you will see an empty Virtual Dashboard when you first load it, and it will ask you to add Hypervisor, you can click in the black space on the right.
You can restore from the old backups, by using the Recover Previous button at the bottom right of the Virtual Dashboard (AVD) dialog.
First, add the Hyper-V and/or VMware server to the new installed NovaBACKUP (NBK).
Open Virtual Dashboard (VD) and add the Hyper-V/VMware host.
For restoring from your external disk open the Virtual Dashboard (VD) and click on the blue button at bottom right hand. If you open the VD for the first time after installation you will see the screen as shown in Image 1:
Image 1
Click "OK" if you did not added a VM before.
Image 2
Click "Recover Previous".
Browse to drive/folder that contains the VD backups.
Select the parent folder of VM backup, e.g.:
Backup was saved to
E:\Import\VMware\VD\AMoRouter
You will find a subfolder "E:\Import\VMware\VD\AMoRouter\NovaBACKUP".
Select folder "E:\Import\VMware\VD\AMoRouter" (see Image 3):
Image 3
Then select VM to restore (e.g. yellow labeled) and click "Recover":
Image 4
Select the date that you want to restore from. 
Image 5
Click "Restore".
Image 6
Select Hyper-V or ESX host as destination for restore (red arrow) and select folder and datastore.
Click "Finish".
Please find more details about the Virtual Dashboard in the AVD manuals/articles:
https://support.novastor.com/hc/en-us/articles/360006791913-NovaBACKUP-Virtual-Dashboard-Quickstart-Guide
https://support.novastor.com/hc/en-us/articles/360006728634-NovaBACKUP-Virtual-Dashboard-VMware-Differential-Backup-Retention-issues
NOTE: If the "Recover Previous" function in NovaBACKUP B.E. Virtual Dashboard (v19.3 and newer) does not work to allow you to import your previous Virtual Dashboard (AVD) produced backups, to list them and show the backup history and provide you with the restore and mount functions to utilize to restore your old VM backup sets, then you can utilize the following guides for Extracting files from a VMware backup set here and from a Hyper-V backup set here.
NOTE: If the Mount or Restore functions in NovaBACKUP B.E. Virtual Dashboard (v19.3 and newer) do not work to allow your Virtual Dashboard (AVD) produced backups to provide you with the restore and mount functions to utilize to restore your old VM backup sets, then you can utilize the following guides for Extracting files from a VMware backup set here and from a Hyper-V backup set here.