Re: Keyboard failure
Turn off PC by holding down power button. After it turns off - unplug from wall.
While unplugged from wall - hold down the power on/off button for 60 seconds (this drains the power from the system).
Plug PC back in and reboot - hopefully, that fixes the issue.
From what I have seen, this is a common problem and the keyboards are fine - Dell does not currently have a solution.