First clue. You can't turn the device off without "pulling the plug' There is something seriously wrong with the device or it's FW has become corrupt.
DavidM:
" I have to pull the power cord because nothing will turn off the computer." < You ment Printer right?
Power cycling should resolve the problem. If it doesn't, and its withing the return period, I'd do that. If outside that, but still under warranty call Canon.