I built a simple code that prints "Hio" in the output. But after the build it says "Cannot open file C:\Hello World access denied." I don't know how to fix this.
When you are using Windows Vista or later, and/or you are not an admin, access to the root folder of your had disk is usually denied by Windows.
To fix, select an output folder to store your data where you have write access, e.g. "My Files" or deeper.