George gets an error message in Microsoft Word that it's not responding as he's typing. After a while it wakes up and catches up. Leo says that the keyboard has a buffer and it will catch up as the buffer dumps out. But it won't catch everything. And George has Windows 10 with Office, so there's something going on in the background that's slowing George down. Windows could be background indexing. He should check the task manager. There may also be plugins from the browser that's slowing things down.
Leo thinks George's hard drive may be at fault here. A sector on the disk may be hard to read and the OS is taking the time to do that. Sometimes it gives up or it gets the data it wants. So the hard drive may be starting to go bad. George should check out Process Explorer from Microsoft SysInternals. Also, if he happens to have SpinRite in his quiver, it could make the hard drive healthier. It's not a cheap program to buy, though.
A new hard drive could fix the problem.