Photoshop CC will not start after latest major Windows 10 update

First, let me get it out of the way that I have already uninstalled and reinstalled Photoshop CC.

Clicking the "Open" button in the Adobe Creative Cloud portal no longer does anything. No error message, just nothing.

Trying to start Photoshop CC 2018 directly from the Windows Start Menu does produce an error. It says "The code execution cannot proceed because VCRUNTIME140.DLL was not found. Reinstalling the program may fix this problem." Unfortunately, reinstalling did not fix the problem.

It was working fine before. Last night I let it install a huge update for Windows (the kind that takes an hour or two, restarts the computer several times, and when it comes back it says something like "Hi, we've made some improvements to your Windows Experience" or whatever, something like that. Ever since then, I've had this problem. Also, I had Photoshop CS5 installed at the same time, and now that program says that my serial number is "no longer valid" and I can't run that either. I'm wondering if the update might have somehow stripped a folder privilege and the Adobe installer can't copy the needed DLL to wherever it is supposed to go. I dunno, but I need this fixed ASAP.