Very Strange

If the SFC scan found no corruption, and the malware scan found nothing, one thing you could try before going for the repair install is to set it for "Open in own window", select OK, then toggle back to "Open in same window", select OK.

Might want to open a couple folders before toggling back to the way you want it. Give it a shot just to see.

Have you made this change in Control Panel>Folder option

Thanks for trying to help me. I solve my problem with restore points.

Pleased to hear you've resolved it. And thanks for posting the fix!!