How to Troubleshoot Problems with the DirectX Diagnostic Tool
One of the least known troubleshooting tools in windows is DirectX Diagnostic Tool (dxdiag.exe), which can be used to solve problems you have with hardware used by multimedia applications, such as audio players or video games. This tutorial presents this tool in detail, shows how to launch it and use it to get the information you need.
What is DirectX?
To quote Wikipedia, "Microsoft DirectX is a collection of application programming interfaces (APIs) for handling tasks related to multimedia, especially game programming and video, on Microsoft platforms."
It is used widely especially for developing games for Windows and Xbox. Therefore, if you have trouble playing games due to stability and performance problems, the DirectX Diagnostic Tool can be used to understand where the problem is. This tool is recommended especially by gaming companies trying to provide support to the players playing their games.
If you want to know more about DirectX, check this very complete article: DirectX (on Wikipedia) .
Starting the DirectX Diagnostic Tool
The fastest way to start the tool is to open the Start Menu and type "dxdiag" in the search box. Then, click the dxdiag.exe search result.
Alternately you can use the Run window  to start the tool using the same command.
The Basics About the DirectX Diagnostic Tool
When you start the DirectX Diagnostic Tool, you see a window similar to the one below. It includes tabs called System, Display, Sound and Input. Some of the tabs can show up multiple times and have the same name plus numbers at the end. This is due to the fact that the tool detected more than one driver for devices providing similar functionality. For example, in the screenshot below I have the Sound 1 and Sound 2 tabs. The first is for my speakers (analog audio output) and the second for SPDIF Out (digital audio output).
The same can be noticed for Display, in case you have multiple monitors.
One of the things I recommend doing is to check the "Check for WHQL digital signatures" box, found at the bottom of the System tab.
This will make the tool evaluate if all the drivers are digitally signed by Microsoft and confirm if they have been tested and approved by Microsoft’s Windows Hardware Quality Labs.
If you are using a 64-bit operating system, the tool first launches and checks the 32-bit drivers installed on your computer. This means that the DirectX Diagnostic Tool won’t show much in terms of information, as your system has 64-bit drivers.
Therefore, click the button which says "Run 64-bit DxDiag".
DirectX Diagnostic Tool will start its 64-bit version and evaluate your hardware configuration and drivers once more.
General System Information
The System tab provides useful information about your computer, such as its name, exact version of the operating system, motherboard (under System Manufacturer and System Model), the BIOS type and version, the processors, memory, data about the page file and the DirectX version installed.
System Display Information
In the Display tab you get important information about your video card and monitor(s). It includes things like: name, manufacturer, exact chip type, video memory information, the monitor and resolution being used and exact information about the driver installed (version, date, etc.).
In the DirectX Features section, you see which of the important DirectX features are enabled.
In the Notes section you can see if problems have been identified. The information being provided can help troubleshoot problems (if any).
System Sound Information
The Sound tab displays information about the audio output options existing on your computer. You get the name and manufacturer of each device, exact information about the drivers installed and, in the Notes field information about the state of their functioning. If there are any problems being identified, you will see them listed there.
System Input Information
Last but not least, you have the Input tab. As the name implies, it shows information about all input devices you have plugged in. These devices generally consist of your mouse, keyboard and gaming pads.
Each type of input devices can be extended and you get to see more and more detailed information about each device, including the exact driver file being uses, version, etc.
Even though Windows 7 provides plenty of troubleshooting tools, the DirectX Diagnostic Tool can still be useful in understanding what’s going on with your system, especially with your video, sound card and input devices. If you have any other tips about using this tool, don’t hesitate to share them in a comment below.