Needed Pop Up Window won't Pop up!

Greetings.

Our business group uses an internet based system for reporting all of our 
programs.  I have two laptops and one desktop.  Everything works great on my 
laptops, but I'm having a problem with the Desktop.

The system our group designed uses a 'calendar icon' that you have to click 
on to pick a date (from the calendar that pops up) that your program took 
place.  Once you click on the appropriate date, the date is populated into 
the report.  However, on my desktop, when I click on the icon, nothing 
happens!  It makes the 'clicking' sound you expect when you want something to 
open, but it does not.  On the bottom title bar it says "javascript"
when I 
hover over the icon.  The date cannot be entered manually...you HAVE to click 
on a date for it to be accpeted...but if the calendar won't pop up...I'm 
stuck.

I'm using Windows XP with all updates current.
My desktop is a Dell.

I figure it has to be something silly that's set in my internet options, but 
for the life of me I can't figure it out.

I hope this makes sense.