my client problem was that :
if you have avast - goto https://www.avast.com/uninstall-utility or http://files.avast.com/iavs9x/avastclear.exe - uninstall it - taskbar is back!
stories on internet :
https://www.google.com/search?q=taskbar+frozen+windows+10
FYI - no work
if for any reason still getting problem (you have todo the trick with PowerShell) :
http://www.tenforums.com/general-support/12321-taskbar-start-button-not-working-post321176.html?s=fbd8b63e8823ee14c4ed439eccea694b#post321176
or
https://answers.microsoft.com/en-us/insider/forum/insider_wintp-insider_desktop/fix-windows-10-taskbar-not-working-fix-build-10074/6b13e8b6-b30b-4e80-aa7c-a4a3939195ea
if you have avast - goto https://www.avast.com/uninstall-utility or http://files.avast.com/iavs9x/avastclear.exe - uninstall it - taskbar is back!
stories on internet :
https://www.google.com/search?q=taskbar+frozen+windows+10
FYI - no work
JavaScript:
sfc /scannowif for any reason still getting problem (you have todo the trick with PowerShell) :
http://www.tenforums.com/general-support/12321-taskbar-start-button-not-working-post321176.html?s=fbd8b63e8823ee14c4ed439eccea694b#post321176
or
https://answers.microsoft.com/en-us/insider/forum/insider_wintp-insider_desktop/fix-windows-10-taskbar-not-working-fix-build-10074/6b13e8b6-b30b-4e80-aa7c-a4a3939195ea