VideoFile locked after viewing with native player

[cyberco]

I use the native player (WMP) to view a movieclip I just recorded using
the following code:

======CODE================
SelectPictureDialog selectPictureDialog = new SelectPictureDialog();
if (DialogResult.OK == selectPictureDialog.ShowDialog()) {
Process process = new Process();
process.StartInfo.FileName = selectPictureDialog.FileName;
process.StartInfo.Verb = "Open";
process.StartInfo.UseShellExecute = true;
process.Start();
}
============================

After closing the player the file stays locked by the player due to the
fact that the player disappears to the background but is not really
closed. How can I really close WMP and unlock the file again?

 

[cyberco]

Or is there a better way to start/stop native applications?