Hi

See section "Creating a Single Setup Project to Install a .NET Framework
Application and Dotnetfx.exe" here:

Redistributing the .NET Framework 1.1
http://msdn.microsoft.com/library/en-us/dnnetdep/html/redistdeploy1_1.asp

also:

NET Framework 1.1 Deployment Guide
http://msdn.microsoft.com/library/en-us/dnnetdep/html/dotnetframedepguid1_1.asp

</quote>
Setup.exe Bootstrapper Sample (includes source code)

The Setup.exe Bootstrapper sample demonstrates how to create a single setup
program that, when launched, installs the Microsoft .NET Framework version
1.1 redistributable package (Dotnetfx.exe) and any required language packs,
if necessary, and then installs a .NET Framework application with a
Microsoft Windows Installer-based setup program (.msi file).
</quote>

--
torgeir
Microsoft MVP Scripting and WMI, Porsgrunn Norway
Administration scripting examples and an ONLINE version of the 1328 page
Scripting Guide: http://www.microsoft.com/technet/scriptcenter

It's tricky to run C# code to detect whether the framework is installed because
the C# code won't run without the framework!
VS Setup projects already have some internal checks for the framework. If you
look at Launch Conditions, you should see one that lets you put the runtime
version you want in the SupportedRuntimes property. So your MSI file won't get
far without the runtime, then you just need a bootstrapper like the one Torgeir
pointed you at to get the framework etc installed before it runs your MSI file.
Here's another one: http://www.codeproject.com/managedcpp/dotnetsetup.asp