What version of Vista are you running, also if you have the Vista installation disc try this !
To resolve this issue, you must perform a repair installation of Windows Vista. Performing a repair installation will restore the current Windows installation to the version of the installation DVD. This also requires the installation of all updates that are not included on the installation DVD.
Follow these steps:
1. Close all applications, and then restart the computer.
2. Insert the Windows Vista DVD in the computer's DVD drive.
3. In the Setup window, click Install Now.
Note If Windows does not automatically detect the DVD, follow these steps:
1. Click Start
Collapse this imageExpand this image
Start button
, and then type Drive:\setup.exe in the Start Search box.
Note The Drive placeholder is the drive letter of the computer's DVD drive.
2. In the Programs list, click Setup.exe.
3. In the Setup window, click Install Now.
4. Click Go online to obtain the latest updates for installation (recommended).
5. Type the CD key if you are prompted to do this.
6. Click Yes to accept the Microsoft Software License Terms.
7. On the Which kind of installation do you want? screen, click Upgrade.
8. When the installation is complete, restart your computer, and then try to install the updates.
Read more on this here: You receive a "0x80070490" error code when you use Windows Update or Microsoft Update Web sites to install updates
Hope this helps you .
Good Luck it worked for me some time ago !
This post has been edited by doinmeedin: 06 November 2009 - 07:15 AM