I can't uninstall it. After my searching I have also come to understand it could be possible by uninstalling sp2 but since my version had sp2 already when installed I don't know how to do it.
I use Vista Ultimate 32bit. Graphics card ati HD5670. RAM 2Gb. Processor AMD Athlon II X2 240 2.80GHz.
It finishes the installation gauge, then give this error message - An internal error occured. Please refer to DXError.log and DirectX.log in your Windows folder to determine problem.
Here is the error log.
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[05/16/11 12:10:54] module: dxupdate(Mar 16 2009), file: dxupdate.cpp, line: 1293, function: CabCallback

Error: (0xe0000233)

File in process: C:\Users\Jaana\AppData\Local\Temp\DX6B8F.tmp\D3DX9_37.dll
Unable to copy C:\Users\Jaana\AppData\Local\Temp\DX6B8F.tmp\D3DX9_37.dll.

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[05/16/11 12:10:54] module: dxupdate(Mar 16 2009), file: dxupdate.cpp, line: 2046, function: ExecuteInf

Failed API: SetupInstallFromInfSection()
Error: (183) - Cannot create a file when that file already exists.



Unable to install C:\Users\Jaana\AppData\Local\Temp\DX6B8F.tmp\D3DX9_37_x86.inf:[x86_install]. The file may be damaged.

--------------------
[05/16/11 12:10:54] module: dxupdate(Mar 16 2009), file: dxupdate.cpp, line: 5858, function: DirectXUpdateInstallPlugIn

ExecuteInf() failed.

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[05/16/11 12:10:54] module: dsetup32(Mar 16 2009), file: dxupdate.cpp, line: 280, function: CSetup::InstallPlugIn

DirectXUpdateInstallPlugIn() failed.

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[05/16/11 12:10:54] module: dsetup32(Mar 16 2009), file: setup.cpp, line: 1701, function: CSetup::SetupForDirectX

InstallPlugIn() failed.

This repeats for every attemp I made judging by the time.