multiple explorer problem

Sir,
In my home computer (windows XP) I had a problem always. suddenly a small window appears inform me about the requested web page isnot available offline and ask me to choose retry or cancel. If i choose either, or just close the window, multiples of explorer windows are appears. If i close them, again and again they are appearing and it cloned like anything and stops the computer to still condition. eventhough I am having panicware’s popup stopper free edition software, it make me sick. please advice me to take immediate action
thanking you
Tamilselvam
btamilselvam@hotmail.com