command not running

I have this code:

$GetBootValue1 = (get-ItemProperty hklm:\SOFTWARE\MGH).OneHour

if ($GetBootValue1 = '1') 

{ remove-itemproperty -path HKLM:\Software\MGH -name OneHour | Start-Sleep -s 30 | shutdown.exe /i /r /t 3600 /c "Your computer will be rebooted in 3 minutes as part our MGH computer maintenance process.  Please close all open program." }