Hi Monika, what I would do is download WinDJView from sourceforge.
It is a really good DjVu viewer, then open your file in that application and click File - Print and use the Windows PDF Printer to convert the DjVu file to PDF
This would be the safe option and will avoid the Bloatware/PUP's that comes with those other apps available on the Web . . .
Hi Monika, that application runs perfectly fine on Windows 10 - I just tested it for you . . .
The reason I suggested that application and website is:
I am a software developer and use that website regularly, That website contains applications written by developers and the code for those applications is also supplied on that website. The applications are well written and do not contain any of the usual
junk you find in free software . . .