At a later date you can sort through both of those folders, save only data files. Do not save/transfer programs, reinstall them fresh; then you can delete those folders as everything else is of now use to the new system.
Next is to format the 1TB spinner, walk though > https://www.lifewire...d-drive-2626077
If you decide to do the standard (long) Format, it will take about 2 to 3 hours for your drive.