How to Fix Error 1603 for Microsoft (R) Net Framework
When you try to install a new version of Microsoft's .NET Framework, you might sometimes get a "1603" or "0x643" error code. This comes up with regard to a failure to install, most commonly because of a corruption in the .NET version you try to install or other versions of the framework you installed before. To stop this error from happening again, you must uninstall all versions of the .NET Framework existing on your computer and install the version you want to install.
Click your "Start" menu and click "Control Panel."
Click "Programs" and click "Programs and Features."
Scroll down to "Microsoft .NET Framework." Uninstall each version by clicking the "Uninstall" button on top of the list of programs with each version selected.
Click the first link in Resources to get to the download page for the .NET Framework. Wait for the download to start and choose where to save the file.
Double-click the installer from the location you downloaded it to. Click "Next" and follow the installation instructions until you must click "Finish." Click the button and restart your computer.