Thank you, Arachne, again for your reply. The Teon disks I used recently were from the same box as those I used a year ago, when there was not a problem at all. Since I don't have another desktop and have no enclosure for this drive, your suggestion to try another PC is temporarily not an option for me.
However, by trying another thing, I did solve the problem. In order to make other users aware of this issue, I am presenting the reason for the burning failure here. The only thing I tried today is to change my PSU. While my current PSU (440Watt) seemed to work ok, I do recall many times that my second hard drive had difficulty being loaded into the system. Even after I changed my motherboard twice, the same problem still existed. So the PSU may be a potential problem. Another thing I forgot to mention was that the system can not recognize the blank dvd disk, and so the burning procedure never began. However, it works well to recognize a blank cd disk and can finish the burning very smoothly. With this in mind, I changed the PSU to a brand new ULTRA 600Watt PSU. The Benq recognized the disk automatically, and began to burn an iso image onto it at the speed of 12x (The printed speed on the disk is 8x). However, the disk burnt was not readable. I then reduced the burning speed to the disk default speed (8x), and it was successful.
I have not done a complete search in the forum, this may have been mentioned many times. But in case some members are not aware of this issue, I am posting my experience here.