Opening Different Chassis

Before opening the case, you must turn the computer off.  Shutdown your operating system as you normally do. On the back of your computer, locate the power switch and turn it off. Some computers do not have a power switch on the back of the computer.

There is no standard for how to open a computer case, which means how you open your case depends on the manufacturer of your case and computer. Below are the three most common methods of how to open a computer case.

Before opening the case, disconnect all the cables from the back of the computer and place it on a table. Next, identify the chassis you're working with. Below is a short list of different ways a computer case cover is held on.

• Screw - Case held on with screws.
• Thumbscrew - Case with screws that require no special tools and can be tightened and loosened with your fingers. Often, these screws also have indents that allow them to also work with tools if needed.
• Screwless - Case that has no screws, only held on with metal or plastic clamps that can release from the case by pressing buttons or switches.

Screw and thumbscrew computer cases
The screws, buttons, or other mechanisms to open a computer case are almost always located on the back edges of a computer. If the case has screws, these will need to be removed before the case cover can be removed.

Note: Often, the power supply screws are also visible from the back of the computer; however, these are often in the middle of the back of the computer case. The screws you want to remove to open the case are always on the outer-edges of the back of the computer.

Once screws have been removed from the back of the case, push the side cover of the computer case towards the back of the computer. Either the side of the computer case will slide off, or the complete cover will be removed.

Note: If you've removed a side of the computer but cannot see the inside of the computer, it's likely the wrong side of the computer case was removed; remove the other side to expose the inside of the computer.

Finally, some computer cases use a combination of thumbscrews and screwless mechanisms to hold on the side of a computer case. If you only needed to remove one on the back of the computer, it's likely you're working with this case.

Screwless computer cases
There are several techniques on how computer and case manufacturers develop a screwless entry chassis. Therefore, keep in mind that the below steps may not apply to your computer case.

As mentioned earlier, screwless computer cases work by using buttons, levers, or push arms. For example, NEC, Dell, and other major computer manufacturers used a popular screwless entry case where a single thumbscrew is removed from the back right side of the computer case, and while the computer is on its side, press and hold in two small levers on the top and bottom and push the side towards the back of the case.

In addition to the above example, a screwless computer case may have similar levers that may be located in other locations such as the bottom of the computer case or the front of the computer.

Finally, there are also several other screwless computer cases that utilize buttons often located on the front bottom portion of the computer case. pressing this button will release the side of the case, allowing it to be removed.