Your HP software is very good to scan covers with. The "descreen" option is available at the "preview scan" page. At the botton of your first picture you have "show a preview scan" checked (leave that there). Select the rest of your settings. Here's what mine looks like (please don't laugh too hard at my pics, I don't know how to copy what's on the screen. I used a digital camera).

I Leave the (default) Sharpen checked to make up for the descreen which takes a little away. Also check the scan with higher bits depth. When your done click scan and your preview scan page should look like this.

After you move the crop lines to where you want them around your scan, select the last tab on the right.

There's the descreen.
You can make a "shortcut" with all your settings so you don't have to select what you want each time. I used "picture to file".