Win7 does not know the DVD drive?

A lot of users who installed WIN7 and Windows Server 2008 R2 will find an embarrassing problem: the DVD drive in the computer can't be recognized, and naturally it can't be used normally. This kind of situation mainly appears on the SATA interface DVD drive, and after inquiry, the root of the problem is actually on the WIN7 system, what is going on?

Microsoft official explanation

This is related to Win7 power management

Microsoft officially acknowledged the existence of this problem and explained it: the reason for this problem is the SATA driver ( Msahci.sys) The new power management feature of Adaptive Link Power Management (ALPM). Some optical drives ALPM enabled does not work and execution, and cause the computer may not recognize. But Microsoft did not provide a patch update for this problem, but recommends that users wait WIN7 SP1. Is our optical drive only idle at this stage? Simply solve this problem yourself.

■Table: These optical drives may be affected

Brand Brand Remarks

Sony Sony BC-5100S/BC-5600S

Pioneer 212CH/217VXL< Br>

TSST Toshiba/Samsung combined brand TS-L633B DVD+/-RW

PLDS Philips/Jianxing merged brand DS-8A3S

Modify power management settings to solve this problem

Exploring problem solving ideas, ALPM is the key

ALPM is the built-in adaptive link power management function of WIN7, and some optical drives can not be recognized by WIN7, which is a problem here. So the best solution is to turn off the ALPM built into WIN7 and re-establish a power management plan.

View existing ALPM

Click "Start" "All Programs" "Accessories" "Command Prompt", we can see a dialog box, enter "Powercfg/l" ", you can see several ALPMs built into the computer. If the user has previously created a power management plan himself, it can be seen here as well.

A few kinds of ALPM built in the computer

Close ALPM

In general, we can only choose one of these power plans, but not shut down. But now we can disable ALPM here. For example, if we want to turn off the "high performance" power plan built into WIN7, enter the following two sets of code:

powercfg.exe-setacvalueindex 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c 0012ee47-9041-4b5d-9b77-535fba8b1442 DAB60367-53FE-4fbc-825E-521D069D2456 0

Powercfg.exe-setdcvalueindex 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c 0012ee47-9041-4b5d-9b77-535fba8b1442 DAB60367-53FE-4fbc-825E-521D069D2456 0< Br>

The "8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c" is the GUID corresponding to the "high performance" power plan. To turn off the power plan, enter the above code, just replace the GUID corresponding to this power plan.

Microsoft official solution address:

http://support.microsoft.com/kb/976187/

Re-establish a new power plan

After the previous operation, several power plans built into WIN7 have been closed. Now we need to establish a new power plan. Of course, if you have already created a power plan yourself, you can use it directly. Do this again. First find "Power Options" in the "Control Panel". Then click "Create Power Plan" in the left menu.

Enter a name for the new power plan in the Plan Name box, and then click Next.

In the "close the display" and "make the computer go to sleep" box, the user can choose according to their own needs. Then click "Create" to complete the operation. At this point, the WIN7 system uses the power plan we created ourselves. Originally, the optical drive that ALPM cannot recognize can be used normally.

Click "Create Power Plan"

Enter New Plan Name

Set Power Plan Parameters

Write at the end: Close ALPM is the solution The key

the entire operation process is to close the ALPM that comes with WIN7, and then create a new one. This closing ALPM is cumbersome because it requires a lot of code to be entered, and the subsequent operations are not complicated. Of course, we also hope that WIN7 SP1 can be released as soon as possible and solve this problem tangibly.