I need to replace the keyboard of my Acer Aspire

Power down the unit and pop the battery out.

Open the screen to expose the trim piece/hinge shield combo.

Unlatch the trim piece without breaking a nail, pulling up one end, gently shifting and pulling up the other end.

Unscrew the two keyboard retainers and shift the keyboard towards the screen for about two millimeters to disengage the front lock. Carefully turn the keyboard over to expose the flat ribbon.

This is the point where usually all the dust and grit from the keyboard falls into the notebook, and care must be taken not to shake the keyboard. An A4 paper sheet to place between notebook and keyboard will come in handy.

There are two model of ribbon catch: one is usually red and has a flat flap which must be lifted backwards, as if it were a lid. The other is light brown or black and has two side latches that must be shifted upwards. Both latch types fit all ribbon models, anyway, so don't be worried about having the wrong keyboard model.

Now you're there, you might want to gently blow dry compressed air to get rid of some of the dust that inevitably accumulates.

To remount the keyboard, just follow the steps in reverse. Do not over-tighten the retainer screws. To make the front lock in the new keyboard engage, you may need to gently push the keyboard down towards the notebook body. If it still doesn't fit, check the metal tabs are where the slots in the notebook are. It might be necessary to very gently bend the tabs to fit the slots with a pair of pliers. Don't overdo it, or the keyboard will clatter (on the plus side, this is usually unnecessary).