A keyboard is like a cat. Neither will listen to you. A keyboard is independent of you. You can hit the K, but if the keyboard wants L, it will do so. Remember, and this is vital, the misspellings or any errors you see are not your fault. I repeat, it is not your fault.
That being said when your keyboard makes a few mistakes, gently finger-slap the keyboard below the space bar or in the corners, your choice. It is a reminder to the keyboard that it needs to be obedient to your writing.
If misspellings persists, which just happened to me, then slap the center of the keyboard. Do so quickly with force. Some keyboards don’t respond to the gentle approach, you must be firm with them. You may have to do this a few times, but the keyboard should improve its behavior during this period.
However, their are some keyboards that will defy you. Some keyboards are agent provocateurs, anti-writing terrorists infiltrating stores to sabotage writers like you without regard for their own well being. When you realize you have one of these insidious, infernal, saboteurs you must slam your open fist into the center of the keyboard. Keys are sure to fly off the board onto your desk or on the floor. Your message must be that their behavior will not be tolerated. You may have to slam your fist into the keyboard a number of times.
After inflicting the severe pounding you may find that a few keys are broken, can not be inserted into their proper place, or the space bar is stuck and will not give you space. It is sad, but there will always be casualties in war and remember this keyboard was trying to drive you insane, to ruin your writing, increase your proofreading time, and give you a heart attack.
I recommend you try various brands, all cheap ones of course, until you find one that will obey you.
I have examples of e-novels created with previous keyboards that obeyed me for a period of time, until they reverted to their feral life. Examples can be found here: http://www.amazon.com/Terry-Nelson/e/B00EEVHN38
In the meantime, I must make a trip to the store as my keyboard destroyed the first draft of this blog and I must buy a new one. The present one will face a firing squad.