System to freezes when trying to read DVD media in Sony DVD-RW drive. Both DRU-510A and DRU-500.

I have a Sony DVD-RW (DRU-510A manufactured 2003), a Sony DVD-RW
(DRU-500 manufactured 2002), and a Pioneer DVD (DVD-115 manufactured
200). I am running a home built PC with a ASRock P4AL-800
(http://www.asrock.com/product/product_p4al-800.htm) and a Intel
Pentium 4 3.0GHz. The OS version is Windows XP SP2 and has automaic
updates enabled.

Both of the Sony DVD drives cause the system to hang whenever DVD media
is placed into the DVD-RW drive. The Pioneer DVD drive works fine. I
can play a DVD or view the contents of a DVD data disk with the Pioneer
drive. Both of the Sony DVD-RW drives work fine when CD media is
placed in them. Both of the Sony drives work fine when I am in SAFE
Mode. In Safe mode I can see the content of the DVD and browse the
entire disk without an issue.

The system freezes after about 10 seconds after DVD media is placed
into the drive.

I have done the following to debug the problem.

1. Upgraded Sony DVD drive firmware
2. Tried three different BIOS versions on my motherboard.
3. Swaped all three drives through the system trying both combinations
of Master or CSEL settings.
4. Adjusted the BIOS settings.
5. Removed all software related to burning CDs including the MS HighMAT
program.
6. Booted into SAFE mode. The DVD drive can read both CDs and DVDs
when in SAFE mode.

I have not tried removing any MS updates or SP2.

The strange thing is that the drives were working well a few months
ago. The system does not have frequent changes made to it.

Any clues?

Andy