Today I got a new keyboard for my Thinkpad SL510, I noticed though that my Ctrl key wasn't working, I tried both and neither worked, but when I used both and pressed v also, it typed "5v" with other key combos it does other things, so the keys themselves cannot be physically broken as nothing happens when I just use one and press v other than v being typed, I plugged in an external keyboard and the Ctrl keys on that worked perfectly, this only happened after I rebooted, a reboot is not helping either, What can I do? my guess is it is a problem with keyboard layout.
Weird. My best suggestion would be to check your keyboard layout is correct in settings - and maybe your bios if it was sold outside the US.
These might help: