Submitting To A Pop-up

I use the following code to submit a form to a pop-up window:

<script>
function cForm(form){
win=window.open('','myWin','toolbars=0');
form.target='myWin'
form.action='http://msn.com'
}
</script>

<form name="sampleform" method="POST" action="/cgi-bin/formsubmit.pl">
<input type="text" name="q"><p>
<input name="button" type="submit" value="New" </p>
</form>

It's designed to run only on PCs running windows 2000 + and IE 6. I have tested it on several PCs without encountering any problems. However, when I run it on my own PC the pop-up simply loads an about:blank page and the action page opens in a new window, so I'm left with 3 windows instead of 2.