DVD-RW Drive won't detect DVD - how to fix?

I have a HP dv7t-1000 laptop with Vista Home Premium (x64 version), and recently replaced its optical drive because the old one maybe faulty and won't read any CD or DVD disks.  The new one (HL-DT-ST DVDRAM GSA-T50N ATA Device) reads CDs fine (music and picture CDs), but won't read DVDs.  After I put in a DVD, it would spin but the Windows Media Center/Play DVD would say it "can not detect a video DVD in the DVD drive.  Insert a video DVD in the drive".  And the HP Quick Play (Play DVD) won't play either, and its sources of DVD lists only C:/ Drive and D:/ HP_Recovery, but not the E:/ DVD Drive although which is showing under Start/Computer.  I have downloaded Windows Media Player Codec 3.9 and deleted UPPER_Filters in the registry, but the problem still exists.  What else should I do to fix this problem?  Thanks in advance.