It looks like the "regular update" is also running, using the wuauserv, eating tons of memory, and CPU time for nothing. Maybe, I had to stop this service for the stand alone update ?
There are many Vista SP2 and Win 7 SP1 users currently reporting problems with slow Windows Updates. The screenshot below shows the CPU consumption for Windows Update on my 32-bit Vista machine during my May 2016 Patch Tuesday updates. The initial "Checking for updates..." phase ran for about 4 hours that month before it found 16 available updates, with svchost.exe constantly consuming ~50% of my CPU (i.e., complete saturation of one of my Intel dual cores) for that entire 4 hours.
Windows Update A svchost 12 May 2016.png 26.12KB
Using Sysinternal's Process Explorer I was able to show that the entire ~50% of my CPU was consumed by the Windows Update service (wuauserv), and more specifically by a thread for the Windows Update Agent (wuaueng.dll). See my post in Kayla's thread Processes in Task Manager During Updates in the Vista Forums for more information on how to use Process Explorer to diagnose if Windows Update components are responsible for the high CPU consumption by svchost.exe.
WU PE svchost wuauserv 14 Apr 2016.png 60KB
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/ (the same webpage mentioned at the bottom of Willy2's instructions for Win 7) that speeds up Windows Update. 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 three 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 current list of Win32K.sys updates on Dalai's webpage as of today (23-Aug-2016) 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); KB3177725 (rel. 09-Aug-2016). You only have to install the updates that are missing from your system, so if you were fully patched as of the end of July 2016 you should only have to manually install the latest KB3177725 (MS16-098: Security Update for Windows Kernel-Mode Drivers: August 9, 2016) before you run Windows Update to install your remaining August 2016 Patch Tuesday updates.
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 in the MS Answers forum will guide you through the process of installing the standalone update packages (.msu files) for your missing Win32K.sys update(s).
32-bit Vista Home Premium SP2 * Firefox v48.0.1 * NIS v220.127.116.11 * MBAM Premium v2.2.1
Edited by lmacri, 23 August 2016 - 03:12 PM.