While I was wasting away at Microsoft PSS, I rather often used an internal website aptly named http://dllhell.  This website would let you enter a DLL name, and it would return all current version numbers, and which application/service pack/etc installed that version.  It was rather useful for a number of things, as you might understand.

Well, I left PSS, and was sad that I could no longer access that website within a week of having left.  I was sad for a while, until I stumbled upon the public version of that very website.  Happiness reigned once again - at least, as much as it can when I've got a problem that requires use of the site... ah well.

Anyway, take a look, and give it a bookmark - you'll be glad you did.

- G