Acquire Windows 7 iso (License not required)
Here is good link.
Download Virtual Box
Install Windows 7 onto your virtual box
After install when prompted for Key, select activate later.
This will work if you just need it for a quick tune or installing a tune for PowerFC (which I am assuming works for W7)
Windows gives you a 30 grace period to activate windows 7 and will it will be fully functional.
This should work as a temp fix, you will need to purchase a key if you are going to use W7 a lot for tuning.
GL.