The results were: "Windows Resource Protection did not find any integrity violations". I am using a standard Microsoft keyboard 300. I tried switching USB ports. I have noticed that when I hold down a character key in a text field, it takes about 5 seconds before the key stops being sent.
Holding down any key for several seconds and then releasing it makes a jingle sound. After which, Windows treats the key as being held down until the same key is pressed again. For example, if I hold down control long enough and then release, I can zoom in/out using the scroll wheel by itself...