Windows 7 SP 1 fresh installed and not updating? svchost stuck at 100% CPU? PC-WELT-Fix Windows Update not helping? WSUS Offline Update not working?

This HOWTO from skanthak worked for me:

[...] Download at least the last cumulative (security) update package for Internet
Explorer 8, 3124275 alias MS16-001, and the latest (security) update package for
the Windows Update Client, currently (September 20, 2016) 3161647; the latter is
available only as part of the "July 2016" (optional) update rollup package
3172605. [...]