Yes, the box is checked and just for curiosity I opened
several different apps to fill the taskbar. I then just
started hitting Ctrl+N to open new IE windows to see if
they would group and they did not.
Originally, my WinXP was an upgrade from WinME so I still
had some WinME characteristics but the buttons were
grouping then. I started running into problems (like
certain items not loading correctly on a restart) so I
decided to install XP fresh instead of an upgrade. This is
when the problem began.
How are you launching your IE windows? It sounds like your IE windows are
being launched in separate processes, which may explain why only your IE
windows are not grouping.