Cannot open file... Access Denied?

Hi, first of all, I am a total noob with unity. And I’m still learning, I am coding and stuff, but before I get too offtopic here, I am having this error message:1615035--98380--$Capture.PNG
Does anyone know how to fix this? I need an answer fast, thanks.

The attachment didnt come up, but what happens is I open unity and it says: Opening file failed. Opening file Assets/Sample Assets/Utility/ObjectResetter.cs failed: Access is denied. And the options are Try Again, Force Quit, and Cancel.

UPDATE:
This is happening with a lot more stuff as well its doing it with particle systems as well.

This has nothing to do with what you are doing in Unity. The permission of the file seems to be the problem. Try to open the project as administrator.

Right Click Unity shortcut > select Run as Administrator