Upgrade to Windows 10 1903

OK, apart from two issues:

• The time on login/lock screen was shown as 12 hour, rather than 24 hour as defined in Regional Settings. This can be fixed by changing two values in the Registry, under Computer\HKEY_USERS\.DEFAULT\Control Panel\International: sShortTime and sTimeFormat. Replace the leading 'h' with 'HH'
• The keyboard, plugged into the one PS/2 port (via a KVM swtich) sometimes was not recognised. The suggested fix is to go to Power Options, "Choose what the power buttons do", "Change Settings that are currently unavailable", then you should be able to deselect "Turn on fast start-up (recommended)".
  I don't think this worked, so I updated to the latest BIOS to see if it made a difference. The issue has not recurred so far, but I am not yet convinced the issue is fixed.