DVD/CD combo drive can't read DVDs in Dell Latitude

Hi,
I recently bought a Dell Latitude C610 1.0 Ghz laptop that came with
256 MB RAM / 20 GB hard drive from a computer show.

It also came with an 8x DVD-ROM/DISK DRIVE MODULE of type "8x DVD/24x
CD" (according to the label on the part). The part number is
18THT-A00.

I booted up the laptop with BIOS version A16. In the BIOS, the DVD
drive was read as "Modular Bay: CD-ROM".

In Windows XP SP2, the Device Manager says it is a "TEAC CD-224E"
drive. The problem I have is that it can only read CDs, not DVDs.
When it tries to read a DVD the LED flashes on and off.

I've read in the Dell discussion forum that this specific part number
really is a DVD-ROM drive... S why is it being detected as a CD drive
only? (I can't post there right now because registration is
temporarily unavailable.)

I installed PowerDVD so that DVD playback drivers would be installed,
but that still did not help matters.

How can I get this drive to read DVDs??