Keyboard - Typing quotes behaves strangely

I'm on Windows 7 Professional.

Since a few months ago, I can no longer type a quote (' or ") anymore by pressing the key once.
Instead, now I have to press the key twice, then backspace.

Oh the other hand, I got a new feature which I don't need: I can now type 'a and it becomes á, etc.

How can I restore my keyboard so I can type quotes normally?