I pushed button on my Dell laptop, but screen is black & its making a clicking noise.

It could be clicking as it is trying to turn the laptop on, but it is not turning on. If this is the case, it could be a few things and I would have a tech look at it. Now if you wan to see if it is just the display and not the laptop itself, you can 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 monitors on it, for the external monitor to work.

If you can see fine on the external monitor, then your attached display, or the ribbon cable that connects it, are your problem.

If you can't see on the external monitor at all, or the problem occurs on the external monitor as well, then it is probably the graphics card/GPU that is the problem, which may require the motherboard be replaced.