the symptoms you describe are present when the control key is stuck on the keyboard, or when the computer has gotten confused about what keys are pressed and what keys aren't, and it thinks the control key is down. sometimes it happens to me with control, or with alt, and i just bang the shift, control and alt keys on both sides of the keyboard randomly and all at the same time, for a couple of seconds, and that usually fixes things for me 🙂
good luck 🙂 things should reset on a computer reboot at any rate.