|Can you "see" the D-link over your lan?|
Are there drivesr for your HP in windows-7; if not how are you trying to drive the HP?
Have you tried another ethernet cable?
Is the D-link connected directly to your router, or is the connection via a homeplug (lan over mains) arrangement? If so, what happens if you temporarily place the D-link adjacent to your router and connect directly that way?