C#/.NET framework availability on various Windows versions or CPUs

Question

I made a Windows Form application targeting .Net 2.0 and x86. Everything runs smooth on my pc but I want to be sure that my app is fully compatible with Windows XP and above. How can I do that?

Is there something else I can do to increase its compatibility? Is downgrading the .NET framwork helpful? Is there any tool to test the compatibility of my .NET app?

I tested my app on an old Windows XP machine and I got an error 0x000013 or something.

Answer 1

Check if suitable .NET Framework is installed on the PC you want to run your application.
Simply install it if there is none installed yet.
Windows 7 came with .NET Framework(v 3.5 " full profile ") preinstalled, Windows XP did not. You can publish your applications and the installation script will check the compatibility for you.

EDIT: I forgot to mention that you can install up to .NET 4.0 on a XP machine. http://www.microsoft.com/en-us/download/details.aspx?id=17851 It should be backward compatible with .NET 2.0 application but there's not a reason to not switch to 4.0.