How to uninstall Service Pack 1 v.165 from windows Vista ? .......only experts can answer !?

I ve tried to uninstall service pack 1 (Windows6.0-KB936330-wave0-X86) pre released update pack which has been expired by using uninstall feature under control panel in INSTALLED UPDATES but all in vain....an error occuuuured with a message that Update cannot be uninstalled as updated files are in use. i want to update Sp1 final released pack over this pre released sp1 and its not uninstalling unfortunately .... now how do i install final released latest sp1 pack then ??????
The pre Released update pack is creating many problems and thus want to remove it any cost .
If there's any expert ...solved out the prob .
Also note that i ve tried the same in Safe Mode ...but same error occured .!

i tried the same as described under :-

1. Click the Start button , click Control Panel, and then click Programs.

2. Under Programs and Features, click View installed updates.

3. On the Uninstall an update page, click Service Pack for Microsoft鈥?Windows (KB936330), and then click Uninstall.

Found this on MS... tried it yet?

"Method for Cause 6

Resolution 1: For users who installed the prerelease update package for Windows Vista SP1

If you have installed a prerelease version of the Windows Vista SP1 update, you must uninstall this version to install the final release of the service pack. To do this, follow these steps:
1. Click Start, type Programs and Features in the Start Search box, and then click Programs and Features in the Programs list. If you are prompted for an administrator password or for confirmation, type the password, or click Continue.
2. In the Tasks pane, click View installed updates.
3. Click Service Pack for Microsoft Windows (KB936330), and then click Uninstall.
Resolution 2: For users who installed the full version of the prerelease of Windows Vista with SP1

If you have installed the full version of the prerelease of Windows Vista with SP1, you must upgrade to the final version of Windows Vista SP1, or you must perform a clean installation of the final version. (Full versions of prereleased software are not licensed to be run after the Beta period.) To do this, follow these steps:
1. Obtain a full version of Windows Vista with SP1. You may be able to download this from the same source that offered you the prerelease version, or you may have to obtain a copy from a local retailer when it is released for sale.
2. Insert the Windows Vista DVD, and then follow instructions about how to install Windows Vista. You must enter a genuine licensed product key when you are asked.
3. At the installation choice screen, you will be offered either the upgrade option or the custom installation option. Select the appropriate option with the understanding that a custom installation choice will cause you to lose access to your data and your installed programs."

1. Click the Start button , click Control Panel, and then click Programs.

2. Under Programs and Features, click View installed updates.

3. On the Uninstall an update page, click Service Pack for Microsoft鈥?Windows (KB936330), and then click Uninstall.

4. Follow the instructions on your screen.