Multiple versions of Visual Studio installed on same computer

Question

Can multiple versions of Visual Studio be installed on the same desktop computer; specifically, can the Express version co-exists with the Professional version?

I am currently using Visual Basic 2010 Express version to learn how it works.  I'm am reading a book on Visual Basic, Professional Visual Basic 2010 and .Net 4, and am finding the Express version is limited in what it has to offer.  I want to go ahead and purchase the Visual Studio 2010 Professional version and install it on my Windows 7 Home Premium desktop computer.  If possible, I would like to keep the Express version on my computer in case there is a problem with the Professional version installation.

I have read other forum responses to questions similar to mine.  However, my question is specifically focused on whether a no-license-required version, the Express version, can co-exist on a computer with a license-required version, the Professional version.