User folders mapped to hdd?
System backups to a network storage or usb hdd?
Most business users won't fill a 120gb ssd.
Windows 8.1 doesn't use more than 30GB for a full install with most business programs and hibernation files (8GB ram). Windows 7 is a little more frugal.
Have you run the windows disk cleanup?Â Have you filled/deleted non essential files?
Perhaps it's just sloppy computer maintenance?