PowerShell 1.0 fails to start, wants some missing snap-in

I get the following error when I attempt to start PowerShell 1.0:

Windows PowerShell terminated with the following error:
 Cannot load Windows PowerShell snap-in Microsoft.PowerShell.Diagnostics because
 of the following error: Could not load file or assembly 'file:///C:\Windows\Sys
tem32\WindowsPowerShell\v1.0\Microsoft.PowerShell.Commands.Diagnostics.dll' or o
ne of its dependencies. The system cannot find the file specified.

Indeed, the file is not present on my system, but it is also not present on other Windows 7 machines I have.

How do I fix this error so I could use PowerShell?  How/where can I remove that snap-in so it would stop asking for it?

I have Windows 7 Home Premium 64-bit

Thanks in Advance!