If the drive's still under warranty. I'd call Dell or Sony tech support - sometimes they can actually help.
Here's a shot in the dark:
A year ago, when my NEC ND-1100A was only pretending to write DVDs, Dell support had me clear the NVRAM. It's been working without problem since then. Don't know why it worked, the Dell tech guy was reading from a script and didn't explain it to me other than to say that I needed to always format the disc before writing to it. I couldn't find any differences in the BIOS setting between before and after that I couldn't change back to where I had it without causing trouble.
What are ESCD and NVRAM?
Clearing the NVRAM on a PnP system can correct a multitude of problems, ranging from modems that will not configure to a hard drive not recognized by the system.
How Do I Clear NVRAM on my Dell
The 1st section -
Dimension 8200, 8100, 4500S, 4300, and 2200 Systems - is the correct set of instuctions for the
XPS. The 2nd set is for the XPS
R, XPS
D, or XPS
V series.
When to use Maintenance Mode
Clearing NVRAM
In the event of a hardware configuration change, it is occasionally necessary to clear NVRAM to allow the system to correctly detect and identify the hardware changes.