Microsoft this week will try to resolve a startup failures issue by uninstalling recently installed updates. But if you want to keep them, here's how to reinstall the updates.

They all used Windows' Control Panel to uninstall iTunes, and the program appeared to be deleted, but when they installed a new copy, their old library was still in place.

Alternatively, if you uninstalled the app because it was problematic, and you want to reinstall it as a fix, the leftovers may cause problems.