Laptops do not require HDCP circuitry to play high definition movies on the laptop screen. HD DVD or Blu-ray movie playback from a laptop to an external display will require an HDCP connection.
For desktop PCs, monitors with DVI input must have an HDCP graphics card to play. If your monitor has analog input (VGA and component), the movie should play as long as it is not protected by the Image Constraint Token (ICT). ICT (which is built into the Advanced Access Copy System copy protection) will automatically reduce the quality of the image produced by a high-definition video disc player to 540 lines of vertical resolution when the player is connected to an analog display. So, when studios enable ICT in their high definition movies, users without HDCP graphics cards can still watch the movie in reduced resolution if they have an analog display. The movie will play, but not in high definition.