If you are trying to open the project file from the Gallery, that "file not found" error message is, most likely, telling you that the project file is no longer stored in the same folder where it was saved. When projects are saved, the folder where those projects are saved is stored by the Project Gallery. However, when/if those project files are moved, the new folder is not saved by the Project Gallery. So, the Project Gallery will always look for the project files in the folder where they were originally saved.
So, if you have ever moved your project files to a different folder, you will need to either move those project files back to the original folder or you will need to select whatever option is available to open those projects from disk instead of from the Project Gallery. Then, you can save the project files back to that same folder. And, the next time you try to open that project file, the Project Gallery should look in the correct folder for the file.
If you do not remember every moving your project files, you will want to determine in which folder the project file was saved. To do so, open the Project Gallery, right click on the project that won't open, then select 'Properties' in the menu that drops down.
When the Properties window opens, the complete path to the folder where the project was saved will be displayed in the 'File Name' box. You should then open Windows Explorer, go to that path, then look for the project file in that folder. If you do not find the project file in that folder, and if you are sure that you did not delete that project file, your only other option would be to search your hard drive for that project file.
For More Help:
Click on the FAQ link at the top of this page
Then, click on the All FAQ's button on the next page
To contact me by email, please send your message to email@example.com