Popup Windows not working...Argh! Please help.

Hi guys,

I'm really hoping someone can help me on this one. I've upgraded a computer from Windows98 to Windows XP Pro and have encountered a problem with POPUP WINDOWS not working. Explorer works well and surfing is not an issue until I click a link where a sub window is supposed to open up...but instead a window opens and is blank. I have installed service pack #1 (SP1) for XP just after installing Java from a link on this site since I thought it was a Java thing. For the life of me I do't know what would stop popup windows from working. I've set internet explorer to default and still no fix.

Please, if you have encountered this I would really appreciate you're advice. The windows worked well in Windows98 so am at a loss to figure this one out as I've done the patches.