A few days ago...
I noticed that my optical drive wasn't showing up in Windows Explorer anymore. This happened a while ago on my old laptop, so I figured I'd do the steps I did before to fix the error. When this didn't fix it. I searched around online a little, but found nothing to made the drive re-appear. The drive still works in my other operating systems (dual-boot setup) and it sounds to me like it's reading the disc... just doesn't show up in Windows. Well, I put it off, and figured I'd deal with it later.
Today, I downloaded the Windows Phone SDK from DreamSpark, which was packaged in an ISO. Daemon tools failed after a few moments with the error code: 8. I looked this up online but I couldn't find anyone else who got error 8. So, I used the Windows 8.1 built-in ISO mounter to open the disc image but to no avail. It gave me a generic error about not being able to mount the file at the moment. I've tried a few things, applied updates, and restarted the computer several times, but the optical drive still won't show up and my computer still won't mount disc images.
I'm assuming the optical drive's sudden disappearance and the operating system's sudden refusal to open ISOs are connected. Any ideas? I can't find anyone on Google who has this same problem (or solutions that work for me). Re-installing Windows is an option but I'd much rather not!
Thanks in advance!