I found this a few days ago when my Edge stopped working. The "Repair Edge" button basically does everything as outlined by Ramiiiiiiil in this Microsoft Answers thread. NOTE: If you download the repair tool it will be shown as Win_Tool<dot>exe<dot>part. You'll need to eliminate the <dot>part for the tool to work.
Need to repair or reinstall Microsoft Edge - Microsoft Community
Before trying the repair tool or using the method described by Ramiiiiiiil, suggest you make a new restore point or system image just in case.