1) You cannot plug a monitor into the VGA connector, on the back of the desktop computer, AND plug a second monitor into a DVI connector, on the back of a desktop computer.
In otherwords you can only plug ONE monitor into the motherboard.
[ The I/O area on the back of the desktop computer, is the Input/Output area. This rectangular area has connections for Input devices, and Output devices.
Examples such as a Mouse, Keyboard, (INPUT), VGA devices, (VGA monitor - Output), USB devices, audio devices, (Speakers - Output. Microphone is an Input device), and so on.
The I/O area has a rectangular metal shield. (Thin metal plate)
Connecting a device in the I/O area, is connecting it directly to the motherboard.
Example of a VGA connector, and VGA cable,http://en.wikipedia.org/wiki/VGA_connector
Example of a DVI cable, and DVI connector,http://en.wikipedia.org/wiki/Digital_Visual_Interface
(There are several variations of DVI connectors.
Scroll down ]
To use dual monitors you need a graphics card also.
Graphics card with a VGA connector, or DVI connector. (Or both)
Monitor with VGA cable, plugs into the I/O area on the back of the desktop computer. (Plugs into the motherboard's graphic chipset)
The second monitor plugs into the graphics card's DVI connector, or VGA connector.
[ Just an example,http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1416091&CatId=3669
On the image of the graphics card on the left;
Go under it to the subheading - + 11 larger images and views.
There are 7 views shown. One is the carton the graphics card comes in. (View 2 from the left)
Going from the left side, count over to the 5th view. Left-click on the 5th view. Shows you the 'business end' of the graphics card.
Starting at the left side it is the HDMI connector, then VGA connector, then DVI connector.
YES, you can plug a VGA monitor, AND a DVI monitor, into this type of graphics card, and have Dual monitors ]
Computer on, Windows running; Put the Installation disk (CD) in the optical drive's tray. (CD/DVD drive)
Load ALL software.
Drivers, and 'Control Panel'.
Graphics card software loaded, close all windows, go back to your desktop screen. Turn the computer off normally.
Unplug the computer from power. Open the computer case.
FOLLOW Anti-Static Precautions.
(Don't know Anti-Static Precautions? Post back in a Comment)
Physically install the graphics card. Close the computer case.
Plug the VGA cable of the Primary monitor, into the VGA connector in the I/O area, on the back of the desktop computer.
Now plug the DVI cable of the Secondary monitor, into the DVI connector on the graphics card.
(The main monitor you use is the Primary monitor. The second monitor you are going to add, is the Secondary monitor )
Plug the computer into power. Both monitors plugged into power, turn them BOTH on.
Turn the computer on.
When Windows loads you will see a display on the Primary monitor.
Your desktop screen.
Now Right-click on an empty area of your desktop screen.
In the list at the bottom, Left-click on - Properties.
In the Display Properties window that comes up, left-click on the -
You will see two rectangular icons. 1 and 2.
1 is the Primary monitor. 2 is the Secondary monitor.
Left-click on the Secondary monitor icon.
Go down towards the bottom/middle on the left.
Left-click in the empty square to the left of -
Extend my Windows desktop onto this monitor
Go down to the bottom Right. Left-click on Apply.
Go down to the bottom Left. Left-click on OK.
Your desktop screen will now be on the secondary monitor.
When you open your internet browser, (Yahoo, or Google, or MSN, or Mozilla Firefox, etc), you have to DRAG the screen onto the secondary monitor.
(Let's use Yahoo for an example. Yahoo will be on your Primary monitor.
You need to drag Yahoo onto the Secondary monitor)
Which direction you drag, is up to which direction the two monitors are sitting, on your computer desk.
The way the monitors are sitting in Display Properties; the Primary monitor is on the Left. ( 1 )
The Secondary monitor ( 2 ) is on the Right.
This is the way the two monitors should sit on your computer desk.
(There is a way to switch them around, however)
On your Primary monitor, (Still using Yahoo as an example), go to the RIGHT side. See the blue frame going around the screen?
When you bring the mouse cursor ON the blue frame, it turns into a Double-Sided arrow.
It is difficult at first to keep the cursor as a double-sided arrow.
Move too far to the right, it turns into the usual pointed cursor.
Move too far to the left, and it turns into the usual pointed cursor.
have to keep it on the blue frame.
WHILE the mouse cursor is a Double-Sided arrow, left-click, and hold the left mouse button down. Now drag the screen to the Right.
(Move your mouse to the right)
Keep dragging until the Yahoo browser is on both monitors.
Different size monitors? The display will not be the same size, on both monitors.
[ I use an HP 2009m, 20-inch widescreen monitor, as a Primary monitor, and an RCA EN-V, 26 inch HDTV, as a Secondary monitor.
I have my desktop on the Primary monitor, and FixYa, (Firefox browser), on the Secondary monitor, right now ]
If this is not your problem please state in a Comment.
Also state additional questions in a Comment.