Re: Cant See Display
When you connect an external monitor you might need to hold the function key (FN) and the display key, which is usually one of the F keys
Some laptops will automatically switch and display on an external screen but not all, so you may have to do it manually.
The problem you have could be a number of things such as a damaged motherboard, graphics chip/card, screen, screen inverter and even just a dislodged or broken cable connecting the screen to the motherboard.
It can be hard to troubleshoot issues like this online and usually are better solved by having someone take a look at it