Dead laptop

Clarifications

however, likely there is a loose cable going to the monitor, or the monitor lights died.

Is there a very faint display on the screen when you power it on?

It could be a corrupted bios. I've seen this when a computer powers on but it doesn't POST, display anything or sound any bios error codes.

I'm not saying this is definitely the problem, but based on your description it would be my first guess.

If you're not comfortable with what I am about to describe, I don't recommend doing them. Take it to a technician

To fix this you need to reset the battery.
It's typically trickier to do with laptops because it almost always involves opening the thing up. When I have to do this I try to find the manufacturer's documentation but you said it's a Packard Bell which means it's A. very old and B. you probably won't find documentation for it. It's possible to find the documentation, just google for it. Finding the docs would be optimum.

I've seen laptops handle this procedure in the following ways:

-Reseat the cmos battery. Open the thing up, find the cmos battery (usually a CR2016 lithium battery, but it can be a different kind). Check the most easily accessed place first.

-Flip a switch. There may need to find a switch (often on the inside), flip it, power it on, power it down, and flip the switch back.

-Move a jumper. Similar procedure to flipping a switch but you move (or remove) a jumper instead.

-unplug power cable: There might be a small power cable inside the computer that you need to disconnect as it provides power to the cmos chip.

My suspicion, based on a solid knowledge of desktops, is that the Hard Drive may be loose. Try removing all drives and see if it will boot. If it will, it's a loose drive. Otherwise, try the BIOS reset described in another post.