function checkOS()
{
	var strOS = navigator.appVersion;
	if (strOS.toLowerCase().indexOf('win') != -1)
		{
		var url='http://machelp.nl/images/stories/WinHelp.zip';    
		window.open(url,'WinHelp',"width=350,height=250");  
		}
	else if (strOS.toLowerCase().indexOf('mac') != -1)
		{
 
		window.location.href='http://machelp.nl/images/stories/MacHelp.zip';

		}
}