How do I convert WMI dates to standard dates and times?

Use the SWbemDateTime object to convert these to regular dates and times.

const
  wbemFlagForwardOnly = $00000020;
var
  FSWbemLocator : OLEVariant;
  FWMIService   : OLEVariant;
  FWbemObjectSet: OLEVariant;
  FWbemObject   : OLEVariant;
  oEnum         : IEnumvariant;
  iValue        : LongWord;
  FWbemDateObj  : OleVariant;
  Dt            : TDateTime;
begin;
  FWbemDateObj  := CreateOleObject('WbemScripting.SWbemDateTime');

  FSWbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
  FWMIService   := FSWbemLocator.ConnectServer('localhost', 'root\CIMV2', '', '');
  FWbemObjectSet:= FWMIService.ExecQuery('SELECT InstallDate FROM Win32_OperatingSystem','WQL',wbemFlagForwardOnly);
  oEnum         := IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;
  if oEnum.Next(1, FWbemObject, iValue) = 0 then
  begin
    FWbemDateObj.Value:=FWbemObject.InstallDate;
    Dt:=FWbemDateObj.GetVarDate;
    Writeln(Format('InstallDate %s',[FormatDateTime('dd mmm yyyy',dt)]));
    Writeln('');
    FWbemObject:=Unassigned;
  end;
end;

How do I determine the time currently configured on a computer?

Use the Win32_LocalTime class.

const
  wbemFlagForwardOnly = $00000020;
var
  FSWbemLocator : OLEVariant;
  FWMIService   : OLEVariant;
  FWbemObjectSet: OLEVariant;
  FWbemObject   : OLEVariant;
  oEnum         : IEnumvariant;
  iValue        : LongWord;
begin;
  FSWbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
  FWMIService   := FSWbemLocator.ConnectServer('localhost', 'root\CIMV2', '', '');
  FWbemObjectSet:= FWMIService.ExecQuery('SELECT * FROM Win32_LocalTime','WQL',wbemFlagForwardOnly);
  oEnum         := IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;
  if oEnum.Next(1, FWbemObject, iValue) = 0 then
  begin
    Writeln(Format('Year          : %d',[Integer(FWbemObject.Year)]));
    Writeln(Format('Month         : %d',[Integer(FWbemObject.Month)]));
    Writeln(Format('Day           : %d',[Integer(FWbemObject.Day)]));
    Writeln(Format('Hour          : %d',[Integer(FWbemObject.Hour)]));
    Writeln(Format('Minute        : %d',[Integer(FWbemObject.Minute)]));
    Writeln(Format('Second        : %d',[Integer(FWbemObject.Second)]));

    Writeln(Format('Day Of Week   : %d',[Integer(FWbemObject.DayOfWeek)]));
    Writeln(Format('Quarter       : %d',[Integer(FWbemObject.Quarter)]));
    Writeln(Format('Week In Month : %d',[Integer(FWbemObject.WeekInMonth )]));
    Writeln('');
    FWbemObject:=Unassigned;
  end;
end;

How do I determine the name of the time zone in which a computer is running?

Use the Win32_TimeZone class and check the value of the Description property.

const
  wbemFlagForwardOnly = $00000020;
var
  FSWbemLocator : OLEVariant;
  FWMIService   : OLEVariant;
  FWbemObjectSet: OLEVariant;
  FWbemObject   : OLEVariant;
  oEnum         : IEnumvariant;
  iValue        : LongWord;
begin;
  FSWbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
  FWMIService   := FSWbemLocator.ConnectServer('localhost', 'root\CIMV2', '', '');
  FWbemObjectSet:= FWMIService.ExecQuery('SELECT * FROM Win32_TimeZone','WQL',wbemFlagForwardOnly);
  oEnum         := IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;
  if oEnum.Next(1, FWbemObject, iValue) = 0 then
  begin
    Writeln(Format('Description   : %s',[String(FWbemObject.Description)]));
    Writeln(Format('Daylight Name : %s',[String(FWbemObject.DaylightName)]));
    Writeln(Format('Standard Name : %s',[String(FWbemObject.StandardName)]));
    Writeln('');
    FWbemObject:=Unassigned;
  end;
end;

This post is based in the MSDN entry WMI Tasks: Dates and Times