Nothing comes up on monitor

[Vaio123]

When I turn on my computer nothing comes up on my monitor. The monitor is connected and working, but no text or any thing shows up on the screen.

The computer is working, I hear the hard drive working for a little while, but it stops. I know the computer is still on because the fan is working.

I need help on what's wrong with my computer. I don't if it is my hard drive or what. My computer is a Packard Bell Platinum 40 computer.