My MacBook isn't starting

Hi I installed the blackberry desktop messenger for mac on my macbook pro 15" and it asked to retart the machine which I did. But since then the machine isn't starting. When I press the button, the display is blank, the light on the button at the front of the laptop indicates that the machine is on standby. The keyboard isn't responding either as I can't switch caps lock on. Can someone kindly guide me on what may be the problem with my machine. I am hoping that it's not the hard drive As I have tons of important data on it.

Best
gregarious

Hold the power button pressed for at least 5 seconds to force shut-down your Mac.

If that doesn't work, take out the battery to get the computer shut down.

Now follow this guide:
1. Press the power button to start the computer.
2. Immediately press and hold the Command (Apple) key and the the "s" key for single-user mode. (Command-S)

Hopefully your computer starts up now. Try to remove the blackberry software. Restart as usual without starting up in single-user mode. Does it work now?