I remember "Enable rotation" with the other options of rotating clockwise and so, just having it activated sometimes made my ship stop steering at all, guns kept working yeh. Try remove it's key from options/controls completely and see if it happens again.
Unless you press "Spacebar" which controls mouse flight mode, and theres no key at enable rotation, Im not sure anymore... using Z kills your engine but you can still turn the ship fine and engines work if you go forward or so. Not sure about other related issues.
Glad to hear that's solved now Yeah, it was basically a thing of checking all buttons for options. I thought of rare/difficult ones to figure out first, and forgot to mention easy things xD