I have already done that still its giving error for files say larger than 15MB.
Error: "Unable to find the uploaded file in directory : C:\inetpub\wwwroot\TestDragDropUpload\Uploads "
Smaller files are uploading without error and are avaliable in specified upload folder.
I have set in web.config - for large file upload -
<httpRuntime maxRequestLength="1000000" executionTimeout="10800"/>