I didn't download that clip you are talking of but even with a VGA connection you should be able to view HD content.
I can view a BD-9 AVC-HD disc on my older PC using a VGA connection to a CRT monitor.
What media player did you try to use??
Have you tried using WMP 11 or MPC-HC?
But as BigMike states, you'd be better off utlizing that DVI connection. Meritline or Newegg has some decently priced cables... your Samsung didn't come with a DVI cable?? Mine did.
Also, depending whether your graphics card has two DVI ports, if so you could use a DVI to HMDI cablew and connect your PC to an HDTV to get full blown HD experience...