I just moved from XP to Windows 7 64bit with a Quad Core 8Gigs RAM, specifically to be able to use multiple instances of Vienna Instruments on Sonar 8.5 (along with the rather monstrous usage eater, Kontakt 3).  I had the exact same problem:  libraries recognized, nothing being seen by the SW.  I wrote to VSL tech support and got nice notes back saying try this and this and this.  I wasn't about to reinstall 7 at this point. I uninstalled and reinstalled the updated VI software, reram Directory Manager, etc., but nothing.  But then I got this note from VSL's Paul Steinbauer:

Hi Bob,
>
>then please restart your computer, then do a search for "vsldirs1.ini" and delete all these files, please.
>
>This should make it work.
>
>Best regards,
>
>Paul Steinbauer

That worked. I did a full search for vsldirs1.ini. There were three (!!!) in various places. I deleted them all, reran the Directory Manager, and lo and behold there were my presets, matrices, etc. etc. I was starting to be afraid that I was never going to get VI to work again. Which would have pretty much p'd me off. But I'm a fan again...

Bob W