Access to the path is denied

Question

Hi Friends,

Why i am getting the below error when i try to delete the image from folder through .net application

System.UnauthorizedAccessException: Access to the path 'Z:\WebApps\DotnetConversion\ITSNET\its_pic1\643825_2.jpg' is denied.

i tried with giving full access to folded.
i tried with giving full access to ASPNET under security tab in properties of the folder
i tried with giving full access to Network Service under security tab in properties of the folder

please help me on this.