I solved this problem by going into settings in windows 10, going to app, clicking on the ArcMap 10.5 icon, clicked uninstall, then in the installation window that pops up I selected the repair option, then followed the install prompts. After this process software worked again without having to register the software or anything like that. Previously I had no problem using ArcMap on Windows 10, it just stopped working and came up with this error one day.
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