You did not specify what you were doing when you got that error. You also did not specify what type of project it is.

For a beginner, the only way to write a program is to start by creating a project. A project is what tells Visual Studio (VS) what it needs to know to do everything for you that it does automatically.

You should starte with a console program. Use "File | New | Project..." and then in the dialog boxes in the tree view on the left expand the Visual C++ node. Then click on Win32. Click on Win32 Console Application. Take the defaults. When you have finished creating the project, use the menus to do "Build | Build Solution". After the project is built you can use "Debug | Start Without Debugging". If you do that then you have created and tested a simple beginner program.

You should get a book to help you with the hundreds of additional questions you will have.

Sounds like you wrote the file outside of the VS. If that is the case then you need to open a project and load it into it. Post how you created the project.

probably because you need to open up a cpp file on the solution explorer panel just right click on source files

a new display box will appear click on add which will send you to a variety of files that you can choose from. click on cpp and whatever name you want to save it as now all you have to do is write code! good luck!