you can download Sherlock - The Codec Detective! 2.0
The Codec Detective helps to determine the codecs installed on computer
and check to see if any of the codecs are broken....
#1- for Dual LAyer burning, only use Verbatim or Taiyo Yuden blanks... read why --> Here!
#2- Looks like your Memorex DVD16+/-DL4RWlD2 is in fact a rebadged LiteOn SOHW-1673S...
....So try to install this latest LiteOn SOHW-1673S' firmware --> JS0D (25th October, 2005) --> found Here!