You've replaced everything that could both be the problem and still be serviceable... so you're probably out of options.
It's not exactly a 'card', but semantics aside, it is almost certainly the graphics chip (which is almost certainly integrated into the system board). FYI, HP dv2000, dv6000 and dv9000 laptops are notorious for graphics failures like these and I've seen this very problem on at least three computers... where the external display appears to be fine, but the picture on the laptop's own LCD is scrambled. Two of those were HP dv models.
I might add that none of those computers worked with an external monitor for very long. Eventually, the laptops totally failed and became unusable. You may have better luck.. I hope you do (if using an external monitor is an option at all, at least).
The system board itself can be replaced too and mail-order services exist which may repair it (you probably won't find anything close to your location). Reballing and/or replacing the graphics assembly or reflowing the board may fix the issue (not knowing what it is, of course, but assuming it is what I think it is).
In any case, the cost is probably a couple to a few hundred bucks.