Some time ago, I tried dual-booting Yosemite with Windows Vista on the same drive, as I don't have access to another. I successfully installed it and almost everything seemingly worked perfectly, with the exception of sound and wifi, I had yet to even try to get my sound working on it, it wasn't a big priority at the time (though next time, I'd like to get it working right away if possible), and I just used an external wifi adapter while running OS X.
Anyway, I noticed when going back on Windows, the generic volume driver would be missing, and the only way to restore it was to do a system restore, which would allow Windows to reinstall it. I feel this could be related to the fact that I didn’t even have sound working on OS X in the first place, but I can’t say for sure. I’m probably incorrect. Anyway, I didn't think much of it at the time, but then a much larger problem occurred.
After waking up from sleep mode on OS X (which had actually worked fine up until this point), HDMI stopped working. My monitor was showing nothing, and I ended up forcing my computer to shut down only to find that HDMI still wasn't working at all. I couldn't see anything, even outside of OS X. I eventually attached another monitor via VGA, which allowed me to see everything again, I then booted into OS X to find that HDMI would work in that, but still nothing else. The only way to fix it was to again to a system restore on Windows.
After that, I removed OS X and I haven’t bothered with it since, however I would still very much like to dual-boot OS X with Windows again. Is there anything I can do to avoid these problems in the future? Thanks in advance.