hsr//////////////////////////////////////////////////////////////
unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;
type
  TOSVersion = (osUnknown, os95, os95OSR2, os98, os98SE, osNT3, osNT4, os2K, osME, osXP);
type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  function GetOS :TOSVersion;
implementation

{$R *.DFM}
function GetOS;
var
  OS :TOSVersionInfo;
begin
  ZeroMemory(@OS,SizeOf(OS));
  OS.dwOSVersionInfoSize:=SizeOf(OS);
  GetVersionEx(OS);
  Result:=osUnknown;
  if OS.dwPlatformId=VER_PLATFORM_WIN32_NT then begin
    case OS.dwMajorVersion of
      3: Result:=osNT3;
      4: Result:=osNT4;
      5: Result:=os2K;
    end;
    if (OS.dwMajorVersion=5) and (OS.dwMinorVersion=1) then
      Result:=osXP;
  end else begin
    if (OS.dwMajorVersion=4) and (OS.dwMinorVersion=0) then begin
      Result:=os95;
      if (Trim(OS.szCSDVersion)='B') then
        Result:=os95OSR2;
    end else
      if (OS.dwMajorVersion=4) and (OS.dwMinorVersion=10) then begin
        Result:=os98;
        if (Trim(OS.szCSDVersion)='A') then
          Result:=os98SE;
      end else
        if (OS.dwMajorVersion=4) and (OS.dwMinorVersion=90) then
          Result:=osME;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
    OSVersion :string;
begin
  case GetOS of
    os95, os95OSR2 : OSVersion:='Windows 95';
    os98, os98SE   : OSVersion:='Windows 98';
    osME           : OSVersion:='Windows Millenium Edition';
    osNT3, osNT4   : OSVersion:='Windows NT';
    os2K           : OSVersion:='Windows 2000';
    osXP           : OSVersion:='Windows XP';
  end;
  showmessage(OSVersion);
end;

end.

msdn에 있는  샘플입니다.
델파이로 변환해서 사용하십시오.

BOOL DisplaySystemVersion()
{
   OSVERSIONINFOEX osvi;
   BOOL bOsVersionInfoEx;

   // Try calling GetVersionEx using the OSVERSIONINFOEX structure.
   // If that fails, try using the OSVERSIONINFO structure.

   ZeroMemory(&osvi, sizeof(OSVERSIONINFOEX));
   osvi.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX);

   if( !(bOsVersionInfoEx = GetVersionEx ((OSVERSIONINFO *) &osvi)) )
   {
      // If OSVERSIONINFOEX doesn't work, try OSVERSIONINFO.
      osvi.dwOSVersionInfoSize = sizeof (OSVERSIONINFO);
      if (! GetVersionEx ( (OSVERSIONINFO *) &osvi) )
         return FALSE;
   }

   switch (osvi.dwPlatformId)
   {
      // Tests for Windows NT product family.
      case VER_PLATFORM_WIN32_NT:

      // Test for the product.

         if ( osvi.dwMajorVersion <= 4 )
            printf("Microsoft Windows NT ");

         if ( osvi.dwMajorVersion == 5 && osvi.dwMinorVersion == 0 )
            printf ("Microsoft Windows 2000 ");


         if( bOsVersionInfoEx )  // Use information from GetVersionEx.
         {
         // Test for the workstation type.
            if ( osvi.wProductType == VER_NT_WORKSTATION )
            {
               if ( osvi.dwMajorVersion == 5 && osvi.dwMinorVersion == 1 )
                  printf ("Microsoft Windows XP ");

               if( osvi.wSuiteMask & VER_SUITE_PERSONAL )
                  printf ( "Home Edition " );
               else
                  printf ( "Professional " );
            }

         // Test for the server type.
            else if ( osvi.wProductType == VER_NT_SERVER )
            {
               if ( osvi.dwMajorVersion == 5 && osvi.dwMinorVersion == 1 )
                  printf ("Microsoft Windows .NET ");

               if( osvi.wSuiteMask & VER_SUITE_DATACENTER )
                  printf ( "DataCenter Server " );
               else if( osvi.wSuiteMask & VER_SUITE_ENTERPRISE )
                  if( osvi.dwMajorVersion == 4 )
                     printf ("Advanced Server " );
                  else
                     printf ( "Enterprise Server " );
               else if ( osvi.wSuiteMask == VER_SUITE_BLADE )
                  printf ( "Web Server " );
               else
                  printf ( "Server " );
            }
         }
         else   // Use the registry on early versions of Windows NT.
         {
            HKEY hKey;
            char szProductType[80];
            DWORD dwBufLen;

            RegOpenKeyEx( HKEY_LOCAL_MACHINE,
               "SYSTEM\CurrentControlSet\Control\ProductOptions",
               0, KEY_QUERY_VALUE, &hKey );
            RegQueryValueEx( hKey, "ProductType", NULL, NULL,
               (LPBYTE) szProductType, &dwBufLen);
            RegCloseKey( hKey );
            if ( lstrcmpi( "WINNT", szProductType) == 0 )
               printf( "Professional " );
            if ( lstrcmpi( "LANMANNT", szProductType) == 0 )
               printf( "Server " );
            if ( lstrcmpi( "SERVERNT", szProductType) == 0 )
               printf( "Advanced Server " );
         }

      // Display version, service pack (if any), and build number.

         if ( osvi.dwMajorVersion <= 4 )
         {
            printf ("version %d.%d %s (Build %d)n",
               osvi.dwMajorVersion,
               osvi.dwMinorVersion,
               osvi.szCSDVersion,
               osvi.dwBuildNumber & 0xFFFF);
         }
         else
         {
            printf ("%s (Build %d)n",
               osvi.szCSDVersion,
               osvi.dwBuildNumber & 0xFFFF);
         }
         break;

      // Test for the Windows 95 product family.
      case VER_PLATFORM_WIN32_WINDOWS:

         if (osvi.dwMajorVersion == 4 && osvi.dwMinorVersion == 0)
         {
             printf ("Microsoft Windows 95 ");
             if ( osvi.szCSDVersion[1] == 'C' || osvi.szCSDVersion[1] == 'B' )
                printf("OSR2 " );
         }

         if (osvi.dwMajorVersion == 4 && osvi.dwMinorVersion == 10)
         {
             printf ("Microsoft Windows 98 ");
             if ( osvi.szCSDVersion[1] == 'A' )
                printf("SE " );
         }

         if (osvi.dwMajorVersion == 4 && osvi.dwMinorVersion == 90)
         {
             printf ("Microsoft Windows Millennium Edition ");
         }
         break;
   }
   return TRUE;
}