I have geniune windows 7 home premium on my sony vaio laptop but now a days it fails to update after 16 % it reverts and restart but before this it was updating successfully this problem comes in the last days of August 2012 and still have please help, is there security center problem of MS or my windows problem it shows some error codes and sometime it never shows and when it shows error code it is 643 i try to find on net and try many troubleshooting methods with the help of ms help center but fails please reply me on my email tbucha2002@yahoo.com

1. For exact analysis look into WindowsUpdate.log 2. Run Windows Readiness Update Tool 3. If nothing helps, revert to previous working copy. Update all except optional items (unless you know that these are harmless.) Regards Milos

Have a look at the update log and see which updates it has failed on. Note the KB's. Download and install them manually. Reset windows update and try again. http://www.sevenforums.com/tutorials/91738-windows-update-reset.html

Hi, First of all, let us run a Windows Update troubleshooter. http://windows.microsoft.com/en-us/windows7/Troubleshoot-problems-with-installing-updates Then, please follow the steps from the link above to fix the issue. If the issue persists, let us check the following services and make sure they were turned on. Background Intelligent Transfer Service Cryptographic Services Windows Modules Installer Windows Installer Windows UpdateKim Zhou TechNet Community Support