No, VPR Matrix doesn't show information.

http://www.vprmatrix.com/products_desktop_2250.asp

That's okay though. I would like you to take a flashlight, and view the motherboard closely. I need to know who made the motherboard, and what the model number is.

FIRST!
With all Due Respect, I would like you to STOP, (Not shouting), using a vacuum to clean the inside of your computer out.

The vacuum creates Static electricity. Static will FRY OUT the hardware components inside your computer. POOF! No computer!

You may have already done this repeatedly, and have had no problems. All it takes is once.

For a test. Put the wand attachment above your head. Bring it to about 1 inch above your hair, parallel to the floor, and the nozzle end beyond the front of your face.

Have someone turn the vacuum on. Your hair lifts up. This is caused by Static.
Thank you for letting me say that.

It is Much better to use a can of compressed air for computers. Yes, I know it costs more, but it's cheaper than buying another computer.
(About $6 to $8 USD)

BEFORE you reach inside your computer, unplug it from power. ALSO, touch the metal frame of the computer case. This will relieve Static from your body.
Now you are safe, and your computer is safe.
(Work on a table. A Bed, Couch, or directly on a carpet floor are High areas of Static)

You may have to move cables to the side, and accidentally touch components inside your PC.

Look in the center of the motherboard. Also look near the edges. One more common place is in-between the expansion slots.

Expansion slots examples are, PCI slot {White in color},
AGP slot, {Usually Brown}
Due to the hardware components listed above in the VPR Matrix link, I don't think you have a PCI-Express slot.

This gives more detail about the PCI expansion slot, and AGP slot, for identification,

http://en.wikipedia.org/wiki/Motherboard

Look at the photo on the upper right of the page. You can click on the photo to enlarge. The long white slots at the top of the motherboard, are PCI slots. The long Brown slot is an AGP slot. All are Expansion Slots.

On the motherboard you will notice ASUS. It is upside down in the photo, and in-between the brown AGP slot, and the third white PCI slot.

That is the motherboard manufacturer's name. Asus
To the left over by the blue ram memory slot is the Model Number.
It's on a white strip.
A8N-VM CSM Revision 1.10

If I have this information I may be able to find the Motherboard Manual.
I will give you the link to it, and also detail out where the Power On switch, (Button) wires go.

They will go to a Front Panel header on the motherboard. We just don't know where yet. (Connector on a motherboard is called a Header)

Don't worry, we'll find out where those wires go.