DirectX is a set of libraries used by the Windows operating system to play multimedia content.

These libraries are used mainly to play games, as many companies of video games develop games using the facilities offered by DirectX technology. This implies that we must have these libraries installed to be able to play certain games.

At present, it is straightforward to install the DirectX libraries since they are built into the Windows operating system and are updated automatically using the “Windows Update” function.

Then, why are there downloadable versions of DirectX? To answer this question, we need to know how these libraries versions systems are named and which one is compatible with different Windows versions. The following list shows the DirectX version and the compatible Windows version:

• Directx 11.2 => Windows 8.1
• Directx 11.1 => Windows 8, Windows 7 SP1
• Directx 11.0 => Windows 7 and Windows Vista SP2
• Directx 10.1 => Windows Vista SP1
• Directx 10.0 => Windows Vista
• Directx 9.0c => Windows XP SP2

Keep in mind that the above table includes only the operating systems that are more representative of Windows and normally are most commonly used for playing video games.

The list is interpreted in the following way: if a game requires DirectX 11 to run, we will need at least Windows 7 or Windows Vista SP2 to run the game. However, if a game requires DirectX 10, and our Operating System is Windows 7, we will be able to play the game without problems because Windows 7 comes with the version of DirectX 11, which is backward compatible. The backward compatibility means that if we have version 11 installed, we can play games that use DirectX 9c or 10.

There are certain occasions when the backward compatibility is not 100% complete, so we need to install older versions of DirectX. This happens on some games that require us to install DirectX 9.0c libraries, although we have more recent libraries.

If we try to run a videogame and it shows an error like this “Error when you start the application because it was not found d3dx9_35.dll. Reinstalling the application may fix the problem“, this indicates that we need to install the 9.0c version of this library.

Here we offer the file needed to download and install the DirectX 9.0c version. We should pay attention when installing the library since the installer will ask us if we want to install the Bing toolbar (Microsoft's browser). We must uncheck this option if we don't want to install this toolbar in our browser.

We must know there is no DirectX 10 version for Windows XP or DirectX 11 for Windows Vista SP1. On the Internet, some sites offer this type of download. We must be careful since they tend to be filed with malware, viruses, or files that can corrupt our operating system.