If you are playing a file in which you cannot seek or a file
that was created without an index, you must use the Pause method to
stop in place rather than using Stop and Play methods.
Note: You can seek to a point in a file by time or by markers.
The CanSeek property returns True only if the file was
created by VidToAsf or WavToAsf. In either case, you must play
the file either from your local hard disk drive or from a NetShow On-Demand
server; an HTTP server will not allow you to seek into a file.
You can seek to a marker only if the file contains markers
and it is stored either locally or on a NetShow On-Demand server
(not on an HTTP server).