|Try another keyboard first. If that works, take the Dell non-working KB, tilt it up and blow compressed air underneath the keys to dislodge any debris. Then Retry the Dell KB.|
It could be a virus too, I have seen Trojan viruses cause key swapping.
It also, it could be a prankster playing a joke as well. Someone could have installed a tweak on your system to do that.
Just another stupid saying...