If your initial "Checking for updates..." phase of Windows Update hangs for long periods of time without throwing an error, this is a widespread problem that currently affects many Vista SP2 and Win 7 SP1 users.
Some users find that "Checking for updates..." will eventually run to completion if you let it run for several hours, but there is also a workaround posted on Dalai's webpage at http://wu.krelay.de/en/ that speeds up Windows Update for most affected users. This workaround requires users to pre-install the Windows kernel-mode driver (Win32K.sys) updates listed on that webpage if any are missing from your system before running Windows Update. I've used Dalai's workaround for the past four Patch Tuesdays (the second Tuesday of each month) and it's reduced my "Checking for updates..." search for available updates from several hours down to approx. 25 min.
The step-by-step instructions posted 16-Jun-2016 in m#l's thread Updates not working, it has been searching for updates for hours are based on Dalai's workaround and will guide you through the process of installing the standalone update packages (.msu files) for your missing Win32K.sys update(s).
As of 13-Sep-2016 the current list of required Win32K.sys updates listed on Dalai's webpage is: KB3078601 (rel. 18-Aug-2015); KB3109094 (rel. 07-Dec-2015); KB3145739 (rel. 12-Apr-2016); KB3164033 (rel. 14-Jun-2016); KB3168965 (rel. 12-Jul-2016); KB3185911 (rel. 13-Sep-2016). You only have to install the Win32K.sys updates that are missing from your system, so if you were fully patched as of the end of August 2016 then STEP # 3 of the instructions in m#l's thread should show that the latest KB3185911 (MS16-106: Security Update for Microsoft Graphics Component: September 13, 2016) is the only Win32K.sys update missing from your system that has to be pre-installed to speed up Windows Update.
If you use Internet Explorer 9 as your default browser and experience any problems downloading the .msu installers from the Microsoft Download Center, try using an alternate browser like Firefox, or download the .msu installers to a USB stick from another computer (IE11 should work okay) and then transfer the files to your Vista desktop. I don't know why, but several Vista SP2 users have reported problems using the Microsoft Download Center this month with their IE9 browser.
32-bit Vista Home Premium SP2 * Firefox v49.0.1 * NIS v184.108.40.206 * MBAM Premium v2.2.1
Edited by lmacri, 02 October 2016 - 06:54 AM.