Adding external monitor to laptop

I plugged a HP monitor,(mfg date 2003, supported Win 2000, XP) into the VGA connector of my laptop computer but my computer does not seem to recognize that there is a monitor connected because the monitor screen shows message "check video cable". The cable is a VGA to VGA and is brand new. The monitor power cable is supplying power to the monitor. My laptop uses Win 7, I tried all 4 options in the display setting and none of them send an image to the monitor( duplicate, extend, projector). Besides no video image being sent to the monitor, when I tried the extend choice in the display settings, still no image being sent to the ext monitor and also my laptop screen goes completely dark and I have to unplug the ext monitor in order to get my desktop screen back on the laptop.
The monitor seems ok. It should be able to work with my laptop, right? If anyone can help with this I'd appreciate it.

Every notebook I have seen requires the user to press a specific Fn + F-key combination to enable the external monitor. Sadly, you didn't tell us what notebook you have but on my notebook, it is Fn + F5.

The monitor seems ok.

Seems? Or is okay? Does the monitor work on another computer?

my laptop is a Sony Vaio with Intel Centrino duo, Windows 7 OS.
The help section suggests opening the display settings. If I press the Windows logo key+P I bring up the display settings. There are 4 choices incl. duplicate, Computer, projector,Extend. None of these choices will cause the computer to recognize the monitor when it is connected to the VGA connector.

my laptop is a Sony Vaio with Intel Centrino duo, Windows 7 OS.
The help section suggests opening the display settings. If I press the Windows logo key+P I bring up the display settings. There are 4 choices incl. duplicate, Computer, projector,Extend. None of these choices will cause the computer to recognize the monitor when it is connected to the VGA connector.

You are talking apples and oranges. Or rather, hardware and software. You MUST deal with the hardware first, as I noted above.

You have to enable sending a signal to the external monitor by pressing the appropriate Function key combination. What does you manual say? Thanks to Slartybart, we see it says, Fn+F7. That enables the hardware (in this case, telling your graphics hardware to send the video signal to the external monitor port.

That has NOTHING to do with Windows or any Windows key. Once you have told the hardware to use that port/monitor too, then you use the Win Key to tell Windows how to use the external monitor.

Thanks everyone for your help.