I was able to run the [link|https://ftp.epson.com/drivers/FW_CD08M4.exe|https://ftp.epson.com/drivers/FW_CD08M4....|new_window=true] after I started my WF-7840 in recovery mode connected with a USB cable.
Recovery Mode = power off printer then hold the 4,7, job status and power button. I did not unplug the printer until it would not restart itself from the recovery mode. After the unplug and restart, I had to remove the ink cartridges and reinsert them. After that it worked!