Need4video Converter 9 is not working since I have Windows 10. The program is not coming up.
This software is not available anymore, in fact it's discontinued along with the website where the software was hosted. There are other applications you can use to convert the files you need.
Video Converters: http://software.informer.com/search/video+converters
Secondly, you can use VidCoder or Handbrake as good solutions for file conversion.