Renumber COM ports in Window 7

Hi,
I can’t renumber my 8 digi neo COM ports since i found that Windows 7 have them “in use” COM3 to COM 12.

I don’t know for what purposes Windows 7 use this COM3 to COM12 and neither how to do to make it free to use for my Digi Neo 8.

For now my Digi neo COM ports are numbered from COM 13 to COM 20 but i need setup for COM3 to COM10.

Any help will be appreciate.

Thank you in advance.