NEC 6750a not recognizing burned CDs

A friend of mine is having problem with his new NEC 6750a writer. It reads already burned CDs and DVDs. It has problem writing CDs. According to Nero and Prassi ONES CDs are burned and ready but when he tries to open his CD, Windows says it has problem connecting to the drive, as if nothing has been writen. Like I sait, pressed CDs and CDs writen by other writers are read without problems. His version of Nero is 6.6.1.4. He is sure he’s not using simulation instead of writing. He has tried 3 differend brand of media with the same result. When he tries to burn on the same CDs he has just a moment ago, the burning process starts as if the CD is empty. I couldn’t find a firmware so he could try and update it.

Anyone with ideas?

Burn with verify and you will probably see that it must be a software/driver problem only.