This question from David Dean came in for ExtremeTech editor, Loyd Case:

If I buy two VGA to DVI-I adapters, will that allow me to view HD content?

Loyd's reply:

It depends on whether you want to watch protected content.

First, you don't need two adapters, unless you want to watch movies on two displays. However, watching protected content, such as Blu-ray or HD DVD movies, on your PC requires that the entire hardware and software chain support HDCP content protection. Which means you need an HDCP-enabled video card, an HCDP-enabled monitor, and software that understands HDCP.

If you lack any of the above, you can still watch HD content, but what you see may be running at a reduced resolution, typically 960 by 540 pixels. If you want the full 1,920-by-1,080 or 1,280-by-720, you'll need an HDCP-enabled graphics card and display, plus the correct software to view the content. PowerDVD Ultra and the latest version of WinDVD both support high-definition playback in the form of Blu-ray or HD DVD movies.