How to open .NEF files without format (Nikon Raw Files) in Windows 10 without Lightroom?

How can I open the Nikon Raw files on my Windows 10 PC without any lightroom or photoshop? The files have a .NEF extension
I know I can open the raw canon file on my Windows 10 by simply double clicking on them … They are in .CR2 format. But I can not open files without Nikons format by double clicking on them. It says that the file is not compatible. Please I need help.