1) Remove ALL power. Remove the AC adapter, (Charger), and Battery.
2) Click on the Blue -
Dell Vostro 3500 Service Manual (8530KB)
[This is a PDF file. The computer you are using now has Adobe Reader on it, which uses PDF files.
After you click on the file name it may take up to 30 seconds, before the first page comes up ]
In the Service Manual click on the blue -
Removing and Replacing Parts
Click on Keyboard in the right list.
The Keyboard Cable STAYS attached to the Keyboard. It removes from the motherboard connector.
There is NO plug connector on the motherboard side, of the Keyboard Cable.
The Keyboard Cable is a FFC. Flat Flex Cable.
This is a general example of a FFC,http://en.wikipedia.org/wiki/File:Flat-Flex-Cable.jpg
Note the flat metal strips. These are Contact Strips. They mate up to Contact Pins, in the motherboard connector.
The Keyboard Cable MUST be reinstalled, as it was in the original position.
For this reason you may wish to make a mark, (Sharpee?), on one side of the Keyboard Cable; and a matching mark on the same side of the Keyboard Cable motherboard connector.
The motherboard connector is a type of ZIF connector.
Zero Insertion Force.
It is rectangular shaped, and composed of two parts, BUT does NOT come completely apart.
The bottom piece is the larger of the two. It is stationary, and mounted to the motherboard.
It is the Body.
The top piece is also rectangular in shape, smaller in size, and is movable. It is the Locking Bar.
The Locking Bar is designed to wedge the Keyboard Cable; in the Body, when in the Locked position. (Closed)
IF, the Locking Bar is removed from the Body, it is Broken.
IF, the Locking Bar is broken, or the Body, you are looking at MOTHERBOARD REPLACEMENT, and why I am being so detailed.
Use your thumbnails, or fingernails, to EASE open the Locking Bar. (Unlocked)
Metal tools have the tendency to slip, and break the motherboard connector.
There are Three types of Locking Bars used, to my knowledge.
(Forgot about one in the past)
The Slide type, and the Flip Up type.
I can't make out in the Service Manual what style is used. I think it is the Flip Up type. However;
Slide Lock Bar,
The Brown tabs pointed out by the Yellow arrows, are the sides of the Locking Bar. These are what is eased forward by the thumbnails.
The distance is 2mm. That is a little more than 1/16th of an Inch, or about the width of this capital letter -> O
Slide Lock Bar,
Flip Up Lock bar,
Flip Up Lock Bar,
For additional questions please post in a Comment.