@ Lin731,
Below is a download link for the latest version of
Nero CD-DVD Speed.
http://www.cdspeed2000.com/files/NeroCDSpeed_4511.zip
Open Nero CD-DVD Speed. On the opening page you will see a Menu Tab with “Benchmark”, “DiscInfo”, DiscQuality, and “ScanDisc”. Insert your suspected problematic Burned DVD in your computer DVD device. On the ScanDisc page check “Read Test” and select 4X speed and then click on “Start”. The Nero CD-DVD Speed ScanDisc surface scan will begin. As stated before a quality properly burned DVD should not have any Bad (Red Sectors) Sector errors.
Best Regards,
bjkg