What version of the .NET framework is installed on Windows XP, Vista, and 7?

From Wikipedia and MSDN:

.NET Framework 1.1: Windows Server 2003.NET Framework 2.0: Windows Server 2003 R2.NET Framework 3.0: Windows Vista, Windows Server 2008.NET Framework 3.5: Windows 7, Windows Server 2008 R2.NET Framework 4.0: n/a.NET Framework 4.5: Windows 8, Windows Server 2012.NET Framework 4.5.1: Windows 8.1, Windows Server 2012 R2.NET Framework 4.5.2: n/a.NET Framework 4.6: Windows 10.NET Framework 4.6.1: Windows 10 v1511.NET Framework 4.6.2: Windows 10 v1607, Windows Server 2016.NET Compact Framework 1.0 (SP2): Windows Mobile 5.0.NET Compact Framework 2.0: Windows Mobile 6.0 

From other SO questions:

• Windows 7 - 3.5
• Vista - 2.0 and 3.0
• XP - not installed
• XP SP2 - not installed
• XP SP3 - not installed

If you want to be certain that you application runs on all of these, you will have to install the framework yourself - use SmallestDotNet.com for this.

I would like to point out, that Windows XP SP3 does NOT have .NET Framework 3.5 (Full profile) installed. I just found out and was scared :-0

Have a look at this similar question 'Is there a way to determine the .NET Framework version from the command line?' in which I posted an answer here. In that answer there is a link to the article on CodeProject that does exactly that...