Operating system: Windows 10 Pro 64-bit
Graphics card: Nvidia GTX 1080Ti
Broken: version 2.82a release, 2.82 release.
Worked: 2.81a release and previous versions.
I was trying to get the nightly build of Makehuman working with Blender 2.82 (at that point my most recent install). When that didn't work I deleted the MakeHuman addon files directly by going to my users->me->Roaming->Blender Foundation->Blender->2.8 and deleted all the files there (stupid, I know, but I was already frustrated and impatient after spending three hours of non-productive time wrestling with my tools rather than creating anything.) Before I did this Blender 2.82 was working perfectly.
I went into Blender 2.8 and noticed that the 'N' sidebar would not display and other commands were not working. I decided I should re-install Blender 2.8 to fix whatever I had done. Using the installer it had me remove 2.8 and then I used it to install 2.8.
Blender runs, but there is nothing under Preferences->System->Cycles Render Devices (it's just an empty section and then below that is the Memory and Limits section). Cycles is no longer a rendering option and I can't turn on CUDA nor add my CPU. Just EEvee or workbench are available.
I tried uninstalling 2.82 and then installed 2.82a hoping it would fix the problem, but the situation is the same.
I have since updated my Nvidia drivers and no change.
I also tried 2.81a that I have installed (I keep a few previous versions) and it runs cycles and allows me to select CUDA and my CPU just fine, so I don't think my system is missing anything that should be there.
Fixed. By deleting the folder entirely under users->user->appdata->roaming->blender foundation->blender 2.8, and then reinstalling blender 2.8 (or 2.8a) solved the issue. So, if this should happen to anyone in the future this is how I solved it.
Sorry for posting before I tested everything.