how to manage other applications data transfers from the web

hello to my friends.
i have a project in c# or .Net:
my project should do manage and do check other applications of windows(for example:internet Download manager,Firefox(Downloader),etc... & every app that can download a file from web. in other words if an application started  downloading a file from the web, my project(custom app c#) should detect it file and save it's File Started Download time. but my application just should write and save file's Download time. in originally IDM(InternetDownloadManager is that should do Download a file)>>>>to means: my app wants access to downloader applications Data transfers from web.
 or access to external application.
how do it in c#?