The Store and Save is an external USB drive, right?
Well, for a start I wouldn't accept that brush-off from PB. When they sold you the drive, did they tell you that it might not work with future versions of Windows? I would go back to them and say that you bought the drive in good faith and that the operating system limitations were not made known to you at the time of purchase. You therefore expect some support guidance with your problem.
However, in the meantime, have you tried having a look in Disk Management, to see whether the drive is recognised? Click Start, right-click on Computer, then left-click on Manage. Now click on Disk Management. Is your external drive listed and shown as Healthy and Active? If so, is it a Primary Partition? Is it formatted FAT32 or NTFS?