Black screen during OS update but computer is on

Hi there.

A friend gave me an old white Macbook I think from 2007, so I turned on and connect it to the WiFi.

I think it had OS X 10.5.1 (Leopard??). There was an OS update, so I went ahead for it. I left the laptop in the room while it was updating, and when I came back the screen was completely black but I kept hearing the laptop working, so I waited for a while but nothing happened, so I turned off the computer and turned on again, but now the screen is always black. The Apple logo in the back is also off.

When I turn it on, I can see a fast blink in the screen, but anything else.

I don't know what happened.

I've been doing some research over the internet and try all the possible solutions, like shortcuts (cmd+R, cmd+P, cmd+F5) and stuff... but nothing solve the problem.

I hope you guys can help me out with this.

I've bought a wire to connect the laptop to an external display, but I'm still waiting for the wire to arrive.

Thanks :)