This sounds a lot like a windows problem. From memory msvcr*.dll stands for the MicroSoft Visual C Runtime, if the linker isn't able to find the DLL maybe something has changed with your $PATH to alter the directories it'll search?
When you installed Visual Studio it should have also added a "Developer Command Prompt" which is essentially just cmd with the correct environment variables set. You may want to see what happens when you try to compile your project in that.
It's not malware, but this computer does have some stability problems I haven't been able to pin down yet. I've run cpu and memory tests and swapped out the motherboard. Beginning to suspect a bad install of Windows 10.
FYI to those out there, I ran into this again today, on a different computer. Reboot didn't help. Had to completely uninstall and reinstall rust to fix the problem. The executable that was looking for the dll was build-script-build.exe, which is apparently an intermediate file in the build system?