[Registry]Root: HKLM; Subkey: "Software\MCS"; ValueType: string; ValueName: "MCSVersion"; ValueData: "1.0.6"; Flags: uninsdeletevalue[Code]function GetMCSVersion(): String;var MCSVersion: String;beginMCSVersion :='';RegQueryStringValue(HKLM, 'Software\MCS', 'MCSVersion', MCSVersion);Result := MCSVersion;end;function InitializeSetup(): Boolean;var MCSVersion: String;beginMCSVersion := GetMCSVersion();result := true;if length(MCSVersion) > 0 then begin//如果发现程序已经安装过了MsgBox ('本程序已经安装，请卸载后再安装本程序. 安装程序将关闭.', mbError, MB_OK);result := false;end;end;