I had bought a Plextor PX716SA SATA DVD RW drive in july 2005. Of late it has developed some problems. My PC configuration is as follows: MSI K8N Neo4 platinum [NVidia Nforce4 chipset] 1GB DDR[400 MHz] RAM 160GB SATA HDD Segate & Antec 380WATT power supply. I have installed Nero burning ROM 7 and PlexTols professional and all the latest drivers for mboard and also upgraded the firmware for the optical drive Both burning softwares show the following errors: Power Calibration error at end of burn process, Invalid write state at end of burn process, Session fixation error while writing LEAD IN, Focusing Error No track or programmable area present. I have used MoserBaer, Verbatim, Samsung, Sony, Kodak, FujiFilm,TDK,etc. but the errors persist. I lost all the blank media used. The same errors occur for CDs and DVDs.