Just had a look at your program and its a great idea we have the same problem with games etc
your program seems to be running from several filesystemwatcher objects which are not designed to detect files opening and after having a look around there only seems to be one way to detect these events in ntfs. by using a file system filter driver you need to download the windows driver kit from ms and in there is a minispy program written in c# once modified for your needs and compiled will give you the results you need to block any file from opening
