If my Thinkpad has the XP mode installed and Windows 7 professional, can I switch between
those operating systems?
Does the Rapid Boot Enhanced Experience 2.0 work in the XP mode?
Also, how do I access the Rapid Boot on the ThinkPad E520?
The XP mode runs under Windows 7 as a virtual computer.
you will find more Additional information here: http://windows.microsoft.com/en-us/windows7/products/features/windows-xp-mode
Therefore there is there is no connection between Rapid Boot and XP Mode
I apologize for asking a dumb question...but that means the Rapid Boot will work
when I'm using XP mode, right?
No a explained in the KB, XP Mode runs inside a virtual Machine... and is in no way connected to the rapid boot functionality which comes with your system.