Open a folder in windows explorer

I am working on an ftp application that will download files from my companies various servers. Once the file has been downloaded a menu will appear and give users the option to click on a link label and open a specified folder that contains the downloaded file. The problem I am having is finding a way to open a folder in windows explorer. Does anyone know how to do this? I have found some examples that use the "shell" command but i can never get it to work. Thanks