On the left side are different views. I am looking at the REAR view
At the Bottom, of the Rear of the computer, are 6 expansion slot openings.
Two of the expansion slot openings have an adapter card in them.
The other 4 are covered with an expansion slot cover. (Metal)
One of the adapter cards is a Graphics Card.
Looking at the Back of the computer, and from Left to Right;
there is a;
1) S-Video port
Black in color, round in shape
2) DVI port
White in color, parallelogram in shape
3) VGA port
Blue in color, parallelogram in shape
This article shows a graphics card with the same setup,http://www.hardwaresecrets.com/fullimage.php?image=879
You can use the S-Video port, or the VGA port, or the DVI port; to connect a monitor.
However out of all three, the DVI port is the best.
VGA is Analog.
Your computer puts out a digital signal. (Digital video signal)
DVI is Digital Visual Interface. In otherwords - Digital.
Therefore DVI is the best.http://en.wikipedia.org/wiki/VGA_connectorhttp://en.wikipedia.org/wiki/Digital_Visual_Interface
Armed with the above information, can you clarify more about your problem?
Monitor cable has three prongs........
Using the above information, can you tell me what monitor cable it is?
Computer has two...........
Can you tell me where on the computer, you are trying to plug the monitor into?
Please post back in a Comment.