In my (limited) experience, I would think not. Oftentimes there are registry changes and certain files tend to be upgraded/overwritten that may cause negative consequences in one or the other of the applications. Not sure if this would change even if you put them into separate directories/drives, but still think you would have a problem because there will likely be system files that both would use that could potentially be corrupted if both apps were loaded.
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"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair."
--Dou