http://blogs.msdn.com/b/vsnetsetup/archive/2010/09/01/net-framework-4-0-installation-with-dep-turned-on.aspxWhen your environment needs DEP to be on on your XP SP3 machine and you want to install .Net framework 4.0, we need to ensure that Handwriting recognition is removed. Symptoms When you try to install .Net framework 4.0 on windows XP SP3 with DEP turneden-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)