Why not try rolling the computer back to the date before SP2 was installed.
It's a tad bothersome but at least you'd affirm or eliminate SP2 as the cause.
I'm sorta lazy, and I suppose I'd rather have the camera working than Vista with SP2.
Actually, since I always save to card, and don't use the USB cord, I've never even bothered to install the Nikon software. Some of the software with the camera kit disc is a trial version (!) or (!)
Since I use Photoshop elements version 5 & 7, both of which have updated camera raw plug-ins for my D-90 (&80) I just bring the files in directly to PSE.
I know there might be some issues with the movies also without the Nikon software, but good lord, have you seen the size of those instruction manuals?
This is probably stupid but, I know you're the administrator on your own machine, but have you right clicked of the installation .exe files and selected "run as administrator? (If you have, please overlook that I mentioned it).