However, the problem is that the option to uninstall DirectX 9 is not in the uninstall Windows programs utility, Add or Remove Programs. So, to do this.
1. Run the Regedit: at Start > click Run and type regedit to open Registry Editor.
2. Navigate to the following registry key:
HKEY_LOCAL_MACHINE\Software\Microsoft\DirectX
3. Delete the DirectX entry, and reboot your computer.
4 .When the system restarts, default DirectX 8.1 version is restored on the system.
5. Run the dxdiag command to confirm the same.
Warning: The registry is an important component of your Windows System. For this reason, you must always make a backup of the registry before making any changes to it. You can do this either by using the File > Export command in the Registry Editor, or by using the Backup and Restore feature of a third-party registry tool.
After uninstalling DirectX, you may run a registry scan using a registry tool to remove any left-over entries and to ensure complete DirectX 9 removal. Next, to reinstall DirectX 9, perform the following steps:
1. 1. Clean boot your system:
1. - At Start > Run, type msconfig, and then press Enter to open the System Configuration utility.
2. - On the General tab, select the Select Startup checkbox, and then clear all options under it.
3. - On the Service tab, select the Hide All Microsoft Services check box and then select the Disable All button.
4. - Select OK to close the dialog box, and then restart the system.
2. 2. Finally, reinstall DirectX 9.
(You can download direct X9 from softpedia or microsoft site)