var
ver: TOSVersionInfo;
begin
ver.dwOSVersionInfoSize := SizeOf(ver);
if GetVersionEx(ver) then
with ver do
label1.Caption := IntToStr(dwMajorVersion) + '.' + IntToStr(dwMinorVersion) + '.' + IntToStr(dwBuildNumber) + ' (' + szCSDVersion + ')'
// 5.1.2600 -- XP(Service Pack 3)
// 6.1.7601 -- Win7(Service Pack 1)
// 6.2.9200 -- Win10()