I understand.
If you navigate to the drive and delete the folder named WD SmartWare this will delete all previous backups performed by the software.
Then launch the WD SmartWare on your new system, (you might need a reboot), you should beable to go to backup and have the ability to run backup again and start over.
You might want to make sure that you have the latest firmware and software available as well. Here is the link if you need it.
http://www.wdc.com/wdproducts/updates/?family=wdsmartware
let me know if you have any additional questions or concerns.
