In 2007 I was a Windows user (not so much anymore). As both a technophile and audiophile, I had a lot of sound cards. At the time I had five in my PC. One was a Yamaha YMF744-based card that had some fun FM synthesis possibilities. One was a Diamond Monster Sound MX300, an aging card that still sounded great thanks to the Aureal Vortex chipset. One was an M-Audio Audiophile 24/96. One was a Sound Blaster Live! And finally, there was a Sound Blaster Audigy 2. And there was a drawer full of other cards that weren't being used due to lack of PCI slots.
They didn't all see use (rarely did I have a reason to do anything with the Live! or the MX300), but they were all beloved pieces of technology.
One of the biggest architectural changes to Windows Vista was moving audio drivers from "kernel space" to "user space". This was in order to make it impossible for a misbehaving video driver to crash the entire operating system. It made total sense -- after all, who likes the bluescreen? But it had consequences.
By 2007, many soundcard manufacturers had gone out of business, and many excellent sound cards by manufacturers still in business had long been discontinued. So it came as no surprise that the release of Windows Vista was accompanied by a statistically insignificant number of working sound cards.
Of the 11 sounds cards I owned, only the $5 Dynex card still worked.
Even Creative Labs, the once-great pioneer of PC audio, had no or only partial support for most of their cards. And they were jerks about not having driver support, alienating many of their customers and effectively destroying what was a large fan base. While the move to software-based audio processing in Windows would have hurt them a bit regardless, their actions resulted in massive layoffs in 2008 and they had to sell and lease back their headquarters in order to stay in business.
Many customers. myself included, still do not trust Creative Labs to this day, and will not do business with them because we see them as waiting for an opportunity to rip us off. And that's on top of their purchasing and subsequently destroying Ensoniq, an amazing synthesizer manufacturer.
The situation is much better now, with a large ecosystem of audio hardware and software support in Windows, and a much stabler system than in XP days, but 2007 was still a very painful year for early adopters.