Sorry, but the situation isn't clear.

The machine should be compatible, yes? Tell more about the hardware please: what CPU, how much RAM, what disk space.

You said the install completed and the computer didn't reboot. But you also say that you did the Easy Transfer of programs and data. But that can only be done after the complete install, so it seems you must have rebooted at least once succesfully after the install and before starting the easy transfer.

All I can suggest: start all over with a fresh install without transferring anything. Only start transferring when the new machine works succesfully and (preferably) you made an image copy of the hard disk so you can go back easily if something goes wrong.
Then give your girlfriend your laptop while you fix this.

Kees