Beginning with PowerShell v3, help is no longer shipped by default. Instead, in order to get help you need to download the help information from the Internet. This only needs to be done once but can be repeated from time to time to get the most current help files. When you use Get-Help for the first time, PowerShell automatically detects that the help files are missing and offers to download them for you. If that fails, or if you want to repeat it later, here is how you download the help files in PowerShell v3:
Launch PowerShell with elevated privileges. Then, enter this command:
Update-Help -UICulture en-us -Force
Replace the desired language. Note that it is quite common for Update-Help to return red error messages. This error message is not necessarily a bad thing. It just tells you for which modules it was unable to locate help files. So if you use 3rd-party modules that have no online help repository yet, they will always trigger the error message.