How do i add and delete environment variables without deleting other values.Currently I am programming an application where I download a file from the FTP server without storing in a disk. I think it is stored in the computer's memory. After downloading the file, the contents of the file is shown in the output. The main purpose of the application is to update the environment variables in every start up of the PC. The source file has 3 fields , enviroment variable , value and action. Thus I am suppose to program the application to add or delete variable when needed. SO when the source file is being modified, the required environment variable will be updated. The program is in C#