1. Turn the computer off.
2. Unplug the computer.
3. Disconnect all of the devices going to the tower. Make note of where your speakers plug in.
4. Using a pilips screwdriver, open up the left side of the tower, that's your left when you are looking at it from the front.
5. Lay the computer on the side that isn't open.
6. Touch the case before you reach inside, everytime you let go of something inside the case, I want you to touch the case as you reach for something else. This is IMPORTANT.
7. Disconnect each cable that you see(going to the optical drive.), ONE AT A TIME, and then plug them back in where they were. Some of them may require you to apply firm pressure.
8. Put the computer back together and test it.