Yes, installing a new program can affect the Windows registry. When you install a program, it adds information to the Windows registry that helps configure and launch the program on your system. This includes references to where files are stored, settings for how the program should run, and other important data related to that specific application. The more applications you install, the larger your Windows registry grows in size which may lead to slowdowns or errors if not managed properly with regular maintenance from an efficient windows registry cleaner tool.