How do you replace the headlight bulb located on a 2001 Chevy Cavalier?

Prop open the hood of the car, grab a straight-edge screwdriver or upholstery removal driver (seems to work better for me) and remove the small, round-headed clips that hold the plastic cover that spans the front of the car over the headlights, then remove the cover itself.
Now, with the cover off, look down directly at the headlight assembly - you'll notice a small rectangular slit cut out right where your headlight lens and signal lens meet.
Grab a long screwdriver and put it down that slit and there is a clip that holds the signal lens in place using the headlight assembly. Use the screwdriver to unclip the signal lens as you pull on the lens to get it loose from the headlight assembly. If you can't see the clip, just grab a flashlight and shine it down into the hold and you'll see it, it's a pretty big clip.
Once you have pulled the signal lens out, you will need a large Torx bit and a ratchet to take off the 2 large silver Torx bolts that are holding the headlight assembly down. You can also use just a regular hex socket of the appropriate size to get these off.
Now with those two bolts removed, it's easy sailing - just pull up on the headlight assembly and out, and now you have easy access to the back of the headlight lens where you will now be able to see where the headlight plugs in.
Around the light is a black plastic locking piece that locks the lens in place - simply twist it off and the light can be taken out of the lens. There's also a blue clip that holds the light into the electrical socket, which can sometimes be a pain in the butt to get off, but just take your time - you don't want to break these parts 'cause they're expensive to replace!
After you have the blue clip off, you can now just take out the light, replace it with your new one (make sure you don't touch the bulb!), and reverse these directions to put the lenses back in properly, and repeat for the other side of the car.

Hope this helps! If you need clarification, just ask.

- Brady H, Ontario, Canada