Help

The other day, literally yesterday, I turned on my computer and noticed that four keys weren't working when I started typing. I can't figure out why; they were working perfectly fine in the evening, but this morning they don't work. Does anyone know what could be causing this? The keys that aren't working are: "2", "ц" (ts), "ы" (y), and "ч" (ch). I don't think it's a keyboard issue because the arrangement of these keys on the keyboard makes that seem highly unlikely. Even if it were, the odds would be incredibly low. Please, if anyone knows how to fix this, let me know. P.S. I typed some of the letters using the on-screen keyboard, so don't think this is a joke.