Yili,
Sorry you are having trouble.
When you ran the setup script, it changed your boot env to boot from TFTP. Do you have a TFTP server up and running? If not, given the going "dark", the board can't boot.
When you plug the SD card into your laptop, it should pop up the "boot" partition in either Windows or your VM. Whichever one, delete the uEnv.txt file and it should get you booting again.
Also, the create SD card script cannot use your internal card reader on your Dell. You'll need to get a USB based reader and make sure it connects to your VM when you plug it in to create a new card.