The code for my pop up is the following:
<a href="http://www.aquariumobsession.com/diseases_diagnosis/diseasesdiagnosis" onclick="window.open('http://www.aquariumobsession.com/diseases_diagnosis/diseasesdiagnosis','popup','width=520,height=610,s crollbars=no,resizable=no,toolbar=no,directories=n o,location=no,menubar=no,status=no,left=0,top=0'); return false">Complete Fish Diseases Diagnosis</a>
on the pop up, to make a link, I am using the same code but with different width and height:
<a href="http://www.aquariumobsession.com/" onclick="window.open('http://www.aquariumobsession.com/','popup','width=1520,height=610,scrollbars=yes,re sizable=yes,toolbar=yes,directories=yes,location=y es,menubar=yes,status=yes,left=0,top=0'); return false">Aquarium Obsession</a>