Windows – What to do when a Windows doesn’t recognize a movie DVD while that disc can be played on DVD player

I've bought a movie DVD which can be run on DVD player. But Windows doesn't recognize the disc. My DVD writer attached with my PC is ok since it can read other DVDs and it supports almost all type of DVDs. If I try to open the DVD from explorer after a long time I can only see a desktop.ini file. I cannot get access to the DVD files from DVD Decrypter, MagicDisc or CDCheck. They all report that there is no disc in the DVD writer. But from Computer Management (Computer > Manage), if I select Storage > Disk Management from left panel, then after a long time, the DVD is shown, showing its capacity 4.67 GB and says that it is online. So certainly Windows can read the files but doesn't let me access! My OS is Windows 7 Ultimate.

How can I copy the files from DVD writer? Thanks in advance.

EDIT:

It is a dual layer DVD. But my dvd writer can read dual layer DVDs I think. Model of the DVD writer: ASUS DRW-1608P3S. Also, there is a text that reads DVD 9 on the disc.

EDIT 2:

Here is the status from AnyDVD:

Summary for drive K: (AnyDVD 6.6.0.7)  
ASUS DRW-1608P3S 1.24 06/05/24PIONEER  
Drive (Hardware) Region: 1

Media is a DVD.  
Booktype: dvd-rom (version 1), Layers: 1  
Total size: 2448000 sectors (4781 MBytes)

However, when I try to copy the DVD using AnyDVD, it says "Drive K: is not ready." I tried both "Rip DVD to harddisk" and "Rip to image" options, and both says the drive isn't ready.