I have a Dell Dimension 4600 and absolutely love it.  But lately, my keyboard and mouse will just stop working.  I usually turn the computer off and on and that helps for a while, but it doesn't ever fix the problem.  I called Dell's technical support once and the women helped me, but the problem surfaced again a few minutes after I got off the phone. 

Also, sometimes instead of not working, the keyboard will type in capital letters when the caps lock is not on. 

Does anyone have any suggestions on what to do?