A couple months ago I bought a new HP desktop at home and it was working great except I kept noticed letters were missing after I typed sentences, passwords, etc. It seemed to happen at random and out of a couple sentences there was usually one letter that would be skipped. I thought it was me at first and maybe I just wasn’t used to the new keyboard, but after I started paying attention and made sure I was striking all the keys I realized it wasn’t me. I reinstalled the keyboard drivers and unplugged the keyboard and plugged it into a different USB port. The problem persisted. I was to the point where I was going to buy a new keyboard when I realized it was only happening in Internet Explorer. I found that disabling the Windows Live add-ons fixed the problem (i.e. Microsoft Live Search Toolbar, Windows Live Sign-in Helper, and Microsoft Live Search Toolbar Helper). I didn’t install those add-ons myself, so they must have came preloaded from HP. To manage your IE add-ons go to Tools -> Internet Options -> Programs and click the Manage add-ons button.