HDCP compatibility issue.....

I recently upgraded my PC to Windows 8 (and upgraded my grahpics card, hard drive). My monitor (ViewSonic VA2248) and graphics card (XFX Radeon HD 7750) is HDCP compatable, yet when I try and play an HD movie I get the error message "To play 'movie name' in HD, you must have a computer with a built-in display or have it connected to a display that supports HDCP".

Could it be a Win. 8 compatibility issue that will eventually resolve itself with an update?

Any help would be appreciated!