shutdown problem in Ubuntu 16.04 LTS ,it restarts every-time?

Question

I feel there is a problem with my Ubuntu desktop ,whenever I try to shut down Ubuntu it always restarts rather shutting down, with Windows there is no such problem. Is anybody else facing same problem ? I am using dual boot ( win7 & Ubuntu 16.04 LTS) and I have updated my grub with sudo update-grub because after installation Ubuntu it didn't detected win7 so I updated grub to get it back at my log in .thank you!