<p>exact code will be helpful. I assume the DirectoryServices namespace does it but I can't find the method that does it.</p>

<hr>

<p>I need actual C# code. All the samples I found so far are VB or VBScript. The C# examples I found are for reading/setting ADSI properties. A command like backup seems to have a certain .NET syntax which I am not clear how to use. In VB there's a straightforward backup command. Need an equivalent in .NET.</p>

You'll need to use ADSI objects. The
IIsComputer.Backup
method is what you want.
As far as how to access ADSI objects from C#, check out this
MSDN page
.
EDIT:
Here's a
sample implementation in C#
.