OK, some details, please.
First, details on the computer. The reason for asking, is in case
it has integrated (chipset) graphics, and a graphics connector
in the I/O plate area (where the keyboard and mouse plug in).
Next, check Device Manager and see how many video devices
are being detected. Do you see an entry for the 210 ? Perhaps
you've already installed the Nvidia driver, and now the 210
is properly labeled.
The Nvidia non-classic control panel, would look like this.
http://img805.imageshack.us/img805/6177/capturenvidia.png
Now, I recollect having up to four rectangles, numbered
one to four, when using two Nvidia FX5200 cards. Each
card is a "dual head", and one card was AGP while the
other was PCI. So I could have up to four monitors,
because I had two GPUs with two monitors each. In this
screen capture, three of the four monitors are "fakes"
caused by using a video connector with terminator resistors
on it. (That is used to activate monitor detection on
the video cards.) The Nvidia cards think they're driving
a couple TVs, and a couple monitors of some sort. Only my primary
monitor had a working EDID, when this picture was taken. Using
a screenshot, was the only way to prove it was in four monitor mode
(since only one real monitor was displaying an image at the time).
http://img197.imageshack.us/img197/6043/extendednvidia128080012.gif
There is a slight change in the video card operating model.
For the last ten years, cards have been dual head, and had
three connectors. You could use any two of three connectors,
with only a few cards violating the rules by having two of
the connectors share the same signals. (A couple cheap
cards, had two connectors, but only ran one display at a time.
The card architecture was dual head, but to save a few pennies,
the second half wasn't connected up.)
The change started with ATI "Eyefinity". As far as I know,
this allows more monitors, but I don't think they have
as much freedom as the dual head situation. For example,
you can have three monitors in panoramic mode. On some
of the high end cards, all the hardware capabilities
are put to usage, and you can have six monitors (two
regular ones, DVI/HDMI, as well as up to four DisplayPort -
the DisplayPort connectors are the "addition" to the
display model).
For the DisplayPort connectors, on those ATI cards, you
sometimes need adapters to use the card with cheap
monitors. Some DisplayPort adapters are passive (and
cheap) - that would be perhaps, conversion from DisplayPort
to HDMI. If you want DisplayPort to VGA, it's possible that
is an active conversion, and the adapter requires power etc.
That would cost a bit more, and in some cases, a cheap
dual head video card would be half the price of buying
active adapters.
http://en.wikipedia.org/wiki/Eyefinity#Multi-display_technologies
That's the ATI story.
I don't think Nvidia has exactly reproduced Eyefinity with
their products.
And since so far, you've only referred to an NVidia product,
I'd have to guess a second GPU is present in the computer,
somewhere. And perhaps Device Manager will show some sign
it is there.
Paul