UpdatedMany people can't install .net framework 3.5. And I was one of them. After many attempts I solved the issue.
Then follow these steps:
- Download "Free Uninstaller 1.1" form this link: http://download.itespresso.it/windows/windows-utility/windows-pulizia-del-sistema/free-uninstaller-11-4544.html In this webpage "Scarica"=Download
- Free Uninstaller 1.1 is a zip package. Doesn't need installation.
- Double click on it and lauch filefun.exe
- Will appear some registry keys red highlighted on the top of the window
- The red highlighted registry keys are invalid registry keys. Remove them.
- Download the updated Aaron Stebner "dotfix cleanup tool" from here in the page top left and launch it. This tool clean your system from any net. framework trace. After cleanup you can safely install the .net framework 3.5.