REAL ANSWER: On the left side of your keyboard is a key that says "Caps Lock".
Press it and all will be caps,
press it again and no caps (unless you hit "Shift" (below Caps Lock) to TEMPORARILY make a capital letter.
I'm betting you may be hitting Caps Lock accidentally sometimes, which can be maddening.
SOLUTION: use a small screwdriver to gently pry the caps lock button from your keyboard.
(It will just pop out. Do it gently to avoid damaging it, and save the button in case you want it back later.) But dont worry even if it does break because you can still activate caps lock even without a button, if you ever really need to. (you'd just press the hole, where the key used to be, with a pen tip.)
You might also like to remove the keys that say "ALT" too,
because those cause freaky unsolvable problems when accidentally pressed.