What do I do when the migration from my old computer to my new computer stalls (saying 135 hours to go), and yet 22,000 files have already been migrated?

What do I do when the migration from my old computer to my new computer stalls (saying 135 hours to go), and yet 22,000 files have already been migrated? Can I start over with a direct wire connection, and not use Wifi? Do I need to delete the files already moved over, so they won't be duplicated?