lablover, See reply #13 in the thread at the link below.
If you have the YAHOO Toolbar installed uninstall it and restart your computer. This has solved this problem for many others.
How to Uninstall the Yahoo! Companion Browser Toolbar
I'm sure I have been able to open a second copy of IE on my Win XP Home PC, with 1024 memory.
Tried to do that this AM, and the second copy does not open as a seconf window. The first one is running, and the second opens on top of the firat.
Is there a setting somewhere that has gotten changed?
Where should I look?