Does your Kindle sometimes start acting sluggish, for no apparent reason? If so, you might have an indexing issue. As you may know, when you download books to your Kindle, your device creates an index for each book to facilitate searching within a book. Most of the time, indexing goes smoothly. But sometimes not. Here's an easy tip to figure out if indexing is your problem. Go to the Search box on your Kindle's main page. The picture below shows what it looks like on a Kindle Touch. If you're using an older Kindle, your search box might look different. Type in a...