I have had an issue on my computer with a rootkit in the past, and it was a pretty serious infection. Lately I have six keys on my keyboard that have suddenly stopped working: m, n, j, h, u, and y. These are all around the middle of the keyboard, (sort of) together, so I thought one of my kids had spilled something on the keyboard, though they promise they haven't. The keys don't stick, they aren't any harder to press down, they feel fine when I type -- they just don't work. I've tried to blow air in to clear out dust, and they still don't work. Is it possible that this problem can be caused by malware?