Hello Alex,
thanks for your answer.
According to the device manager, the DVD writer works fine, no yellow signs are shown.
I've performed a driver update, but the results are equal.
DVD's from other brands like Philips and Fuji are working without any problems.
The TX 4X-speed DVD-RW don't even work on an other device (Laptop, brand of writer unknown). There's the same reaction, No Recognition.
Andreas