If they are all in one location and you want to delete every file then click on one file then press CTRL+A to highlight them all. Then click on Del on your keyboard. BEWARE this will delete every file in that folder so if there is a mixture of good and duplicates then DON'T do this instead try this. Are the duplicates al named "Copy 0f *". If so double click the filename folder header in Windows Explorer to sort the files into alphabetical order. Then click on the first file and then hold down the Shift key whilst clicking on the last file you wish to delete. That should select all the files you want to delete and leave the others un-highlighted. Then click the Del key on your keyboard.
Dell XPS 13 9370 (2018) review