My HTC 8s Stuck while updating to Windows 8.1, what should I do?

[Windows Central Question]

My HTC 8s Stuck while updating to windows 8.1

Today morning I think to update my HTC 8S from windows 8 to 8.1 so I downloaded and installed preview for developers. Then I did what it said.. after that I tap settings> phone update and tap update.. It shows 3 updates.. so I download them.. 1st 2 updates are downloaded and installed perfectly. 3rd update said that it is the 8.1 update.. It downloaded completely.. while in installation those wheels are still spinning.. Now it's nearly 3 hours.. what should I do now? please help me...

Thank you...