Keyboard problems normally fall into three categories. First being stuck or missing keys (ie key presses don't register). Second the "Num Lock", "Caps Lock", etc don't light up. Or the dreaded, "Keyboard not found", sometimes visible or the system is intelligent enough to assume it's operating headless. If the problem relates to the first and not the second as well, The problem refers to dust or other impurities getting between the contacts. Most keyboards built within the last 15 years rely on a rubberized pad that is pressed against the circuit board completing a connection. Often little Bill or Steve has dumped, coffee or slurpee into the keyboard. The solution involves taking apart the keyboard and gently cleaning out any dust or caked on coffee or slurpee. The safest solution I have found is water, using a damp and not dripping cloth, gently clean off any visible contaminants. Then allow the component to dry for at least a day or two before re-assembling. Test again, if the problem persists try cleaning again or replace. If you're keys with LED's don't light up (do they work but not light up?), the problem could be a dead LED. Either learn to deal without, or get your soldiering iron and start replacing (watch your LED anode & cathode). Lastly, the keyboard may have a damaged cable or circuit board, the problem is normally a break or short in the cable. For those who are adventurous, or can't afford to replace, now is the time to break out the multimeter. With the multimeter, you will be needing to test continuity of the tail. Often this is challenging because the colour codes don't reflect any specific pin locations. Record the pin numbers and colour codes for later. At this point if it's only 1 broken wire, with an assistant ask them to slowly start flexing the wire in 1 to 2" lengths, when you suddenly have continuity you've found the damaged section. In the best case you will simply be shortening the cable length to bypass this point, otherwise you will need to wire up a new cable to completely replace the old one. If you find that no wires are broken, you will most likely need to replace. As the problem in that case relates to a damaged circuit board or chip. To return <-- Article by Slam, Last Updated June 2004