If there are sounds inside the device, meaning it is actually on and the display just isn't, and you couldn't see anything on an external monitor, then your graphics card/GPU is probably toast and needs to be replaced. Which may mean the motherboard needs to be replaced.
You may want to try an external monitor again first, using the instructions below, to make sure it actually won't show. Most times just connecting the monitor when the device is on doesn't work.
Try this...
1. Turn the laptop off (not sleep or hibernate but off).
2. Connect an external monitor to the laptop.
3. Turn on the external monitor.
4. Turn on the laptop.
NOTE: You may have to press an "external monitor" button. Could be the f4 button or a button with two...