If you want to make a completely new copy (a clone) of your code from your existing codebase then you could use the template feature of VS. This would let you create a completely new project using your old project as a template.

Project/Export Template... then follow the prompts.

However there seem to be some bugs in the export (particularly for large projects with multiple folders) so you'll need to check the folders of the newly created project contain all the original files you want. I have opened a bug report with MS about this.