For anyone else experiencing this issue, the problem is not Antivirus and the problem is not hard drive dying.
If we look at this error, the listed file path is C:\Users\<name>\Desktop\war3.mpq which is not the proper place for finding a Warcraft III game MPQ archive. Instead, these tools should be configured to tell the tool that the Warcraft III game install is located in a specific location.
The most likely cause of this issue is clicking OK on the "Select Game Directory" popup without selecting a directory in which case it may default to desktop. If that happens, press WindowsKey+R and then type in %AppData% to open the hidden App Data folder. Inside this folder, there will be a folder called JWC3 or maybe MatrixEater depending on your version.
Typically I don't think about this folder and 5 years ago when I was using Matrix Eater before I created the Retera Model Studio to use instead, back then I would use View -> Change Game Directory or whatever it was that would show the popup asking the user to locate the Warcraft 3 game again. But when the software has a bug and is failing to open at all, so that it becomes impossible to change this setting, that is when the best solution is to go to the App Data folder mentioned above.
Inside the App Data folder for these programs, there is a file called user.profile that contains the file path chosen by the user. In this case, it probably has the incorrect value of C:\Users\<name>\Desktop and that is causing the problem. If you delete or rename user.profile then all of these settings will be reset and you will have the option to choose a new directory where the Warcraft III game is installed.
As a side note, for Linux and Mac users there is no app data folder so the user.profile is located in the hidden dotfile folder located at ~/.jwc3 or ~/.matrixEater.
