The solution that DVD drive cannot be used under Win7 system

Windows 7 does not recognize certain DVD drives. This is not a DVD issue, but a Windows 7 issue. Microsoft officials have explained that this problem is due to the new power management features of the SATA driver (Msahci.sys) Adaptive Link Power Management (ALPM), which causes some CD-ROM ALPM features to be enabled and disabled to work properly and may cause the computer to be unrecognizable.
If your DVD drive happens to fall into this category, take a closer look at the solution below!
1, first check to see if Windows 7 does not recognize your DVD device. Just in the device manager is just a yellow exclamation mark showing a problem with the data signature, or the prompt "Windows can't verify the data signature of this device ……" and so on.
The specific symptoms may be as follows:

2, the solution, there are two:
The first method: modify the registry
start-> run-> regedit-> Open the Registry Editor and expand:
HKEY_LOCAL_MACHINE/SYSTEM/Current ControlSet/Control/Class/{4D36E965-E325-11CE-BFC1-08002BE10318}
Remove the Upperfilter and Loweverfilter items in the right frame and restart computer.
Note: When you delete the above two values, you may lose some features, such as CD recorders. If this happens, you must reinstall the affected program. If the problem persists, you may need to contact the program vendor to see if there is an updated version of this program.
Second method: Command line method
Click “Start -> All programs -> Attachments", right click on the command prompt & rdquo; Run as administrator”.

Paste the following command after the command prompt cursor and press Enter:
bcdedit /set loadoptions DDISABLE_INTEGRITY_CHECKS
This solves the problem that the DVD drive cannot be recognized and cannot be used under Windows 7.