Swapping a USB keyboard generally doesn’t require a restart, but that will usually fix any problems. And using the not-yet-unplugged old keyboard is the best way to make sure you can shut the computer down cleanly.
Some electronics are sensitive to static, so a warm, humid day would be best. You could let a humidifier run in the area for a few hours first if the air is dry: heated winter air generally is. You could use a wrist strap and other antistatic devices[2] X Research source when handling the electronic parts, but they’re unwieldy, and keyboards are tough and cheap as electronics go.
Turn the keyboard upside down and remove the screws from the back. Sometimes, a plastic case may be held together partly by one or more screws hidden under a sticker. If so, poke into and slice around the edges of a round depression or lump in it with a small knife, or just poke a screwdriver through. In an area that would show, gently lift up the edge of the sticker with a knife (a blunt one will often do) and peel it up, lifting more than rolling back so as not to crease it, impart a strong bend that won’t go back down, or damage the surface. If you remove it entirely, set it sticky-side-up out of harm’s way until time to replace it. Sometimes a plastic case may be held together by an interlocking tab at an edge. If so, lift out the other edge first or bend one or both mating parts to free it. Sometimes a case may be held together by screws extending from the top into the bottom, such as screws under the spacebar, which pops off, on a Microsoft Natural Ergonomic 4000, or screws under stickers. When you have the bottom free, set the keyboard on a table to complete disassembly so its parts don’t dump out before you see how they all fit together.
Case screws. You already loosened these to free the bottom cover. Take them out and set them aside or carefully set the bottom aside with them still in the holes so they don’t fall and get lost. Bottom cover. Multi-layer keyboard membrane set of thin, non-stretchy plastic with electrical circuit traces. Keep this together so that dirt doesn’t get between the layers and put it aside. It’s delicate and possibly susceptible to water damage, so don’t clean it except to gently wipe off any excess dirt. Notice that it has holes which fit over pegs in the top cover to keep it from sliding around under the set of keys which is supposed to tap it in particular places to indicate what is being pressed. If it is held down somehow, remove whatever is holding it down. Unscrew screws and wiggle it past or cut off any bits of plastic holding it. Do not cut the membrane itself! Notice that the keyboard has an electrical connection to some electronics themselves connected to the USB cable. If those are permanently connected, remove them from the keyboard with the membrane. If it’s removable, check that it can connect only one way or note how it connects. On the Microsoft Natural Elite keyboard, the membrane has a set of contacts at an edge that press between a rubber pad in a pocket and a set of contacts on the edge of a rigid printed circuit board that lays over it. [3] X Research source One or more silicone sheets of dome switches to provide one dome per key. Notice that the domes face the keys, which would kink them to tap the membrane, and that, like the membrane, they fit over pegs to keep them from sliding around. They don’t themselves contain any electronic parts, so wipe them or even wash them gently if you like, but make sure they are dry before reassembling the keyboard. One or more key assemblies - banks of keys in plastic frames. On an old keyboard, these probably have lots of dirt that might even interfere with their smooth travel. Blow it out from between the keys with a small blower or canned air. Wash them if you like, even in a dishwasher (away from the heating element, which could melt them) but make sure they are dry before reassembling the keyboard. It’s not easy to remove the keys from their plastic carriers and you might break something trying. If the keys of the to-be-removed number pad are mounted in a common assembly with others, such as the navigation keys, remove the keys in the leftmost row of the number pad for room to work in cutting the assembly. It’s best to put the risk of mistakes closest to the keys you don’t want, and, depending on the keyboard’s design, a plastic rib remaining on the number-pad side will help anchor the truncated key assembly securely in position with the truncated keyboard case. On the Microsoft Natural Elite keyboard, a key is best removed by squeezing catches on the back and pushing it through the frame. In some keyboards, such as the Microsoft Natural Ergonomic 4000, the key assemblies may be affixed to the top cover. It’s OK to leave them there, but take extra care to get out the plastic shavings after cutting off the number pad so they don’t interfere with the keyboard’s operation. Num Lock, Caps Lock, and Scroll Lock indicator lights. These may be attached to another electronic assembly or, as with the Microsoft Natural Elite keyboard, rest on contacts on the membrane. Check the orientation of the assembly and its contacts. Even if it appears symmetrical at first glance, it may have to go back in a particular orientation. Note which end faces a particular way on tape attached to the assembly before removing it if there is a risk of confusion. Cord and main circuit board. On the Microsoft Natural Elite keyboard, the cord is woven through several small gaps in the top cover to diffuse and relieve strain from pulls on it before leading to the circuit board, which connects to the membrane with an edge connector that rests against the membrane, which in turn is pressed down by a rubber pad. Set this assembly, and the pad, aside. Spacebar and its separate dome switch. Some keyboards may not have a separate dome switch or mounting for the space bar, but the Microsoft Natural Elite keyboard does. Take out the dome switch so it doesn’t collect plastic shavings (dirt tends to cling to the silicone), and remove the spacebar too. Top cover. If you’ve removed everything electronic from it, you can wash it. You can wash the bottom cover, too.
If the keyboard case has stick-on or otherwise removable feet where you will cut, or on the part you will cut off, peel them off and set them aside to leave the adhesive untouched, and stick them at uncushioned corners after you reassemble the keyboard.
Save the removed pieces. You might be able to use part of the removed bottom cover, especially if it was cut off perfectly straight, to close up the cut edge of the keyboard. You can use sandpaper to smooth very-rough areas. But it will create many fine, messy plastic particles. Don’t turn a fairly straight, rough edge into a smooth, wavy edge through uneven sanding if you plan to attach a flat, rigid cover to the cut edge. A sanding block to hold the paper flat would help avoid this and the gaps it would leave. Unless you’re going to glue a rigid plate over the entire cut end, you can gently round the cut corners by stroking a flat file around them a few times for appearance. Since the rounded profile will look good, but the cut edge won’t, keep the file in a vertical plane. You could use sandpaper on a flat surface or in a sanding block instead of a file. Once you’ve finished cutting and grinding, remove the tape and open the keyboard case again so you can clean out the shavings.
Wrap it underneath the bottom edge of the keyboard and hold its edge in place with cellophane tape. This is quick and easy. But it looks sloppy. It leaves the membrane vulnerable to contamination, especially from spills–though those aren’t much of a risk in a dedicated keyboard drawer. It leaves the keyboard unsuitable for placement on surfaces that might press on the membrane and thereby register keystrokes, such as the user’s lap. If the keyboard erroneously registers keystrokes from the flap, try shielding one of its layers from the other with plastic wrap. You could still tuck it under, rather than into, the keyboard. In that case, don’t put plastic wrap over the spot the tape is to attach. Prevent it from registering keystrokes by separating its two outer layers from one another and other surfaces with plastic wrap, then tuck it back into the keyboard. This looks much better, and protects the flap from the environment. But it risks damaging the membrane and thus killing the keyboard by bending and breaking it or flaking off its circuit traces, either immediately or over time. It also risks mechanical and electrical interference with the keys it’s tucked under, usually the navigation keys. To do this, cut a strip of plastic wrap a little longer than the length of the protruding membrane flap (which, with standard plastic-wrap width of 12"/30cm or so, will be much wider). Draw the plastic wrap around the bottom layer of the membrane flap, which needs to be separated not only from the top flap but from the bottom flap area nearby inside the keyboard case which it will be bent up against. Pair up the cut edges at the right edge and the top or bottom edge of the plastic wrap (whichever isn’t wrapped) and press them together so they cling. Keep the plastic wrap only one layer thick and trim off any great excess extending past the membrane layer edge. A 1/2 inch (1 cm) margin is plenty. You could try plastic tape instead of plastic wrap. It would stay in place readily. But attempting to remove it, as you might want to try if something doesn’t work initially, could damage the circuit traces–possibly invisibly–and kill the keyboard. Turn the keyboard over and loosen the screws holding the number-pad side of it together, and if necessary the others, so that the cut edge of the keyboard can loosen by a small fraction of an inch (a few mm). Bend over the membrane flap, all layers together, and tuck it in under the navigation keys’ adjacent membrane. You may have to tuck the membrane flap in at a slight angle to best accommodate the screws and other obstructions extending through the keyboard. Leave at least the very edge of the fold out so that it doesn’t get creased hard and possibly soon break on its own. You could roll up the flap, too, but it might be harder to store or cover if it is rolled up and under tension to expand than if it is simply bent over. Folding the membrane into many layers (which will bulge around the folded edges, inside and outside the keyboard enclosure) to tuck into a small space will likely make it too thick and press on the adjacent navigation key switches from underneath. So, you may be left with most of it tucked in and a little sticking out at the keyboard edge. Ignoring that works great. You could cover the cut edge of the keyboard with wide, strong tape such as mailing tape, a hard cover of another material, or even a flat piece of plastic made from the cut-off piece of the bottom cover, tipped upward. If you use tape, and have to remove the tape, carefully free it from the plastic wrap or you may pull that off and have to replace it. If you use part of the bottom cover, you may have to remove or trim down its rim and ribs, and mark its inside edge for cutting by reference to the contour of the edge of the top cover above the bottom cover. After cleaning the mating surfaces, you could attach the plate made from the bottom cover or other rigid material with glue, solvent cement, or strong double-sided tape suitable for the materials involved. If glued or cemented, they would probably have to be held firmly with a device such as a strap clamp until dry. Attaching an improvised cover with a strong adhesive or cement could frustrate opening the keyboard later.
