How to install apps which require older .NET Framework?

[Sadeq]

I'm using Vista, which by default ships with .NET Runtime 3.0. I have
also installed VS 2005, which has both runtime and SDK for .NET 2.0.

Every now and then, I bump into applications which require older .NET
frameworks, such as 1.0 or 1.1. A nice trick I learned previously was
to monitor the setup for registry access (using a tool such as
"Process Monitor"). This showed me that such apps require a special
key in the registry which if set to correct value, you can set newer
frameworks to "act" as older ones. Here's an example:

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\Policy\Standards
\v1.1.4322]
"v2.0.50727"=dword:0000c627

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\Policy\Standards
\v2.0.31113]
"v2.0.50727"=dword:0000c627

Those two keys/values "tell" applications in need of frameworks
v1.1.4322 or v2.0.31113 to use v2.0.50727.

Such registry "hack" worked very good for me, but recently I
downloaded "Application Compatibility Toolkit" from microsoft, which
requires framework 1.1, and does not accept the hack.

My question is: How to tell the application to use newer frameworks?

(I want to install older frameworks as a last resort, and only in case
I'm assured that there's no alternative)

 

[Phil Wilson]

I'm curious as to why you're so reluctant to just install the framework the
app needs, but anyway you don't really need a hack, you probably just need a
config file with a supportedRuntime element.
http://msdn2.microsoft.com/en-us/library/9w519wzk.aspx

 

[Sadeq]

I'm curious as to why you're so reluctant to just install the framework the app needs

That's because I don't want to fill my hard disk with various
installed versions of .NET Framework, and don't want to keep many
dotnetfx.exe files, only the latest one.

And also, in my experience, I saw that newer .NET Frameworks run apps
compiled by older versions of .NET Framework like a charm.

but anyway you don't really need a hack, you probably just need a
config file with a supportedRuntime element.
http://msdn2.microsoft.com/en-us/library/9w519wzk.aspx

I think I can't apply this to MSI setup files. The setup checks for a
specific version of .NET framework, and does not allow me to install
the app b4 installing the older version of framework.