Windows Update funktioniert nicht mehr – was tun?
Tool von Microsoft: Reparieren von Windows Update
Microsoft Fix it

Windows 10 Disable Auto-Restart

How to *disable* automatic reboots in Windows 10?
How to prevent Windows 10 from restarting the computer after installing updates
Configure Automatic Updates using Registry Editor
PennState WSUS Client Configuration

HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\WindowsUpdate\AU

AUOptions   Reg_DWORD   Range = 2|3|4|5
                        - 2 = Notify before download.
                        - 3 = Automatically download and
                              notify of installation.
                        - 4 = Automatically download and
                              schedule installation. Only valid
                              if values exist for ScheduledInstallDay
                              and ScheduledInstallTime.
                        - 5 = Automatic Updates is required and users
                              can configure it.

Windows Update doesn’t work => high CPU/Memory

Windows Update doesn’t work and consumes 100% of CPU (Win7 SP1)
=> KB 3102810: Installing and searching for updates is slow and high CPU usage occurs in Windows 7 and Windows Server 2008 R2
svchost.exe high memory usage – wuauserv
=> KB 3050265: Windows Update Client for Windows 7: June 2015
=> KB 3138612: Windows Update Client for Windows 7 and Windows Server 2008 R2: March 2016