hi i upgrade my hp z400 workstation to windows 10 pro

[gman]

hi i upgrade my hp z400 workstation to windows 10 pro round a year ago but now its all messed up and need clean reinstall but no windows 10 pro iso.. and if i use recovery drive gos back to windows 7 any help guys /girls on how can find a windows 10 pro iso
so can load it on usb thanks

[Compton]