Something

<script language="javascript" type="text/javascript">
var requiredversion = 6; 
var useredirect = true;                     
var flashpage   = "main.html"
var noflashpage = "noflash.html"
var upgradepage = "upgrade.html"
var flash2installed = false;
var flash3installed = false;
var flash4installed = false;
var flash5installed = false;
var flash6installed = false;
var flash7installed = false;
var flash8installed = false;
var flash9installed = false;
var maxversion = 9;
var actualversion = 0;
var hasrightversion = false;
var jsversion = 1.0;
</script>
<script language="javascript1.1" type="text/javascript">
var isie  = (navigator.appversion.indexof("msie") != -1) ? true : false; 
var iswin = (navigator.appversion.tolowercase().indexof("win") != -1) ? true : false;
jsversion = 1.1;
if(isie && iswin){
  document.write('<scr' + 'ipt language=vbscript\> \n');
  document.write('on error resume next \n');
  document.write('flash2installed = (isobject(createobject("shockwaveflash.shockwaveflash.2"))) \n');
  document.write('flash3installed = (isobject(createobject("shockwaveflash.shockwaveflash.3"))) \n');
  document.write('flash4installed = (isobject(createobject("shockwaveflash.shockwaveflash.4"))) \n');
  document.write('flash5installed = (isobject(createobject("shockwaveflash.shockwaveflash.5"))) \n');  
  document.write('flash6installed = (isobject(createobject("shockwaveflash.shockwaveflash.6"))) \n');  
  document.write('flash7installed = (isobject(createobject("shockwaveflash.shockwaveflash.7"))) \n');
  document.write('flash8installed = (isobject(createobject("shockwaveflash.shockwaveflash.8"))) \n');
  document.write('flash9installed = (isobject(createobject("shockwaveflash.shockwaveflash.9"))) \n');
  document.write('<\/scr' + 'ipt\> \n');
  }

</script>
<script language="javascript" type="text/javascript">
function detectflash() {  
  if (navigator.plugins) {
    if (navigator.plugins["shockwave flash 2.0"]
        || navigator.plugins["shockwave flash"]) {
      var isversion2 = navigator.plugins["shockwave flash 2.0"] ? " 2.0" : "";
      var flashdescription = navigator.plugins["shockwave flash" + isversion2].description;
      var flashversion = parseint(flashdescription.substring(16));
      flash2installed = flashversion == 2;    
      flash3installed = flashversion == 3;
      flash4installed = flashversion == 4;
      flash5installed = flashversion == 5;
      flash6installed = flashversion == 6;
      flash7installed = flashversion == 7;
      flash8installed = flashversion == 8;
      flash9installed = flashversion >= 9;
    }
  }
   for (var i = 2; i <= maxversion; i++) {  
    if (eval("flash" + i + "installed") == true) actualversion = i;
  }
  if(navigator.useragent.indexof("webtv") != -1) actualversion = 4;  
  if (actualversion >= requiredversion) {
       if (useredirect) {
           if(jsversion > 1.0) {
              window.location.replace(flashpage);  
      } else {
              window.location = flashpage;
      }
    }
    hasrightversion = true;                
  } else {  
       if (useredirect) {
        if(jsversion > 1.0) {
        window.location.replace((actualversion >= 2) ? upgradepage : noflashpage);
      } else {
        window.location = (actualversion >= 2) ? upgradepage : noflashpage;
      }
    }
  }
}

detectflash(); 
</script>