1. Technology
You can opt-out at any time. Please refer to our privacy policy for contact information.

Step by Step Guide to Deleting the UpperFilters and LowerFilters Registry Values


6 of 15

Determine and Click on the Correct Class GUID
CDROM GUID Class Registry Key

CDROM GUID Class Registry Key

Each of these long, cryptic registry keys that you see under Class corresponds to a Globally Unique Identifier (GUID) representing a specific kind of hardware in your computer.

For example, the GUID 4D36E968-E325-11CE-BFC1-08002BE10318 (which is represented in the Windows Registry by the {4D36E968-E325-11CE-BFC1-08002BE10318} registry key) corresponds to the Display class which includes video adapters.

What you need to do is figure out the GUID for the type of hardware that you're seeing the device manager error code for. You can do that by referencing this list:

Device Class GUIDs for Popular Types of Hardware

For example, let's say your DVD or Blu-Ray drive is showing a Code 39 error in Device Manager. According to the list I linked to above, DVD and Blu-Ray devices belong to the CDROM class and the GUID for that class is 4D36E965-E325-11CE-BFC1-08002BE10318.

Once you determine the correct GUID, click once on the corresponding registry key. There is no need to expand this key.

Tip: Many of these GUIDs look the same but I assure you they are not. They are all unique. It might help to know that in many cases, the difference from GUID to GUID is in the first set of numbers and letters, not the last.

©2014 About.com. All rights reserved.