How do I reinstall Apple Software Update in Windows? I uninstalled Apple Software Update in my Boot Camp Windows 7 install as it was crashing every launch, and a repair of Apple Software Update through Programs and Features didn't fix the problem.

However, re-running Boot Camp Tools' setup.exe (it gives me a choice to do a repair) does not reinstall the Apple Software Update it initially installed.

I suppose you could be in the same situation if you chose not to use Software Update when prompted during the Boot Camp Tools install.

How do I install the Apple Software Update associated with Boot Camp when Boot Camp is already installed?
Ah, Software Update can be reinstalled by running AppleSoftwareUpdate.msi in the Boot Camp Windows support files under Drivers Apple

(To get the Boot Camp Windows support files, boot into Mac OS and use Boot Camp Assistant to save them to e.g. a USB drive that Windows will be able to read -- see https://apple.stackexchange.com/a/247252/5231)