When I type 1 then 2 appears, 2 is 3, 3 is 4, backspace is 0, etc. It is not the number lock, any other options, besides a big sledge hammer.

Hmm. That does sound a little strange. Maybe something in between the keys are stuck together, or something maybe loose. Have staples check it out. Good luck.

Is it a wired or wireless keyboard? If wireless, check the batteries.

Have you tried rebooting your computer?

Is this a desktop or a laptop. If a desktop try a different keyboard. It would appear that something is wrong sending the wrong signal to the computer when you press the keys. If it's a laptop it will probably need servicing.