Code 31 Error Message
The Code 31 error is one of several Device Manager error codes. The Code 31 error will almost always display in the following way:
"This device is not working properly because Windows cannot load the drivers required for this device. (Code 31)"
Details on Device Manager error codes like Code 31 are available in the Device Status area in the device's properties: How to View a Device's Status in Device Manager.
Important: Device Manager error codes are exclusive to Device Manager. If you see the Code 31 error elsewhere in Windows, chances are it's a system error code which you should not troubleshoot as a Device Manager issue.
Cause of the Code 31 Error
A Code 31 error is caused by any number of reasons that prevents Windows from loading the driver for the particular hardware device. Regardless of the root cause, troubleshooting an error Code 31 is pretty straightforward.
Note: If you see the Code 31 error on the Microsoft ISATAP adapter in Windows Vista, you can ignore the error. According to Microsoft, there is no actual issue.
Restart your computer if you haven't done so already.
There is always the remote possibility that the Code 31 error you're seeing was caused by some temporary issue with Device Manager. If so, a simple reboot might fix the Code 31.
Did you install a device or make a change in Device Manager just before the Code 31 error appeared? If so, it's very possible that the change you made caused the Code 31 error.
Undo the change if you can, restart your PC, and then check again for the Code 31 error.
Depending on the changes you made, some solutions might include:
Remove or reconfigure the newly installed device.
Roll back the driver to a version prior to your update.
Use System Restore to undo recent Device Manager related changes.
Delete the UpperFilters and LowerFilters registry values. A common cause of Code 31 errors is the corruption of two registry values in the DVD/CD-ROM Drive Class registry key.
Note: Deleting similar values in the Windows Registry could also be the solution to a Code 31 error that appears on a device other than a DVD or CD drive. The UpperFilters/LowerFilters tutorial linked above will show you exactly what you need to do.
Update the drivers for the device. Installing the latest manufacturer supplied drivers for a device with the Code 31 error is a likely fix for this problem.
Replace the hardware. As a last resort, you might need to replace the hardware that has the Code 31 error.
It's also possible that the device is not compatible with this version of Windows. You can check the Windows HCL to be sure.
Note: If you're convinced that hardware isn't the cause of this particular Code 31 error, you could try a repair install of Windows. If that doesn't work, try a clean install of Windows. I don't recommend doing either of those before you try replacing the hardware, but you may have to give them a shot if you're out of other options.