I had a problem that I had tried to fix once before. I would be happily working along, and suddenly the keyboard would not function properly anymore. It would act as if I were holding down a command key like Alt or Ctrl. (Note: this is different from the problem of unwanted double-keying.)
For instance, with this sticky Ctrl or Alt key problem, if I was in Microsoft Word, pressing the right-arrow key would not take me one space to the right; it would take me one word to the right. In Windows Explorer, clicking on another file would not deselect the first one and select this new one; it would instead add the second one to the selection, so now I would have two files highlighted.
For a while, I fixed this problem by rebooting. That got to be tiresome. Eventually, I tried some of the options suggested on the discussions that came up in a search. Those efforts excluded some possibilities. It wasn’t the keyboard: using a different one did not fix the problem. I wasn’t using a wireless keyboard. Cycling through the command keys (i.e., pressing Tab, then Shift, then Ctrl, then WinKey, then Alt, and then going back through in reverse order, Alt-WinKey-Ctrl-Shift-Tab) didn’t do it. Tapping one or more command keys twice in a row (e.g., Alt-Alt) didn’t do it. Holding down a command key while clicking on a different window didn’t do it. Going into Control Panel > Ease of Access Center > Make the keyboard easier to use, and toggling “Turn on Sticky Keys” (i.e., turn on, click Apply, turn off, click Apply) didn’t do it. There was no particular reason to think it was malware (and I had long since tired of the kinds of instructions that required me to turn off, delete, reset, reprogram, uninstall, and otherwise completely screw up my system, in hopes of turning up something).
What worked for me was to realize that there is a difference between the right and left Ctrl, Alt, and Windows keys. I had no idea what, exactly, that difference might be. But on one occasion, simply pressing the right (instead of the left) Ctrl key solved it. Another time, that didn’t do it — but fiddling around with those same keys did. At this point, it seemed that the solution might be to work through all of these command keys, hitting each one once (and then hammering on them repeatedly, in frustration if that didn’t work): left-Tab, left-Shift, left-Alt, left-WinKey, and then likewise on the right side.
In a later post, I noted that starting Moo0 System Monitor seemed, for some reason, to fix the problem. I would usually choose the right-click “iconize” option to minimize Moo0, and then bring it back to foreground by clicking its icon in my Start > Programs menu, so I didn’t know if other people, using Moo0 in other configurations, would have a similar outcome.