Why does Windows XP Service Pack 2 stop BIRSt working?

With XP service pack 2 Microsoft added popup blocking software. This is because some popup windows contain inappropriate or dangerous content. BIRSt has no such content, however popup windows on the BIRSt website are blocked, preventing the play window from opening.

When you click the button...

You will see the 'pop-up blocked' message...

You may also see the 'information bar' message. Click 'OK' to dismiss it.

Click on 'click here' and choose 'Always Allow Pop-ups from This Site'

Click 'Yes'. Content on BIRSt can now be played. Popups on other websites will still be blocked.