Set the cutting depth of a circular saw to the thickness of the flooring plus 1/8 inch. You will need to make a series of cuts through the flooring so you can pry it up. The blade may cut slightly into the subfloor and leave grooves, but it is essential that it cut completely through the flooring.
Make a straight cut in the seam between two courses of flooring that extends from one wall to the other. When you're finished, make a similar cut in a seam between two courses about a foot from the first one.
Cut the area between the two lines into sections by making a series of perpendicular cuts about 12 to 15 inches apart. Extend the perpendicular cuts a few inches beyond the main ones to be sure you completely cut through the boards.
Pry out each section in turn. Work a pry bar into one of the perpendicular cuts and under a board by hitting it with a mini sledgehammer. When you have enough purchase, pry up the end of the board and, if possible, pull the board straight up and remove it. Since the boards are connected by their tongues and grooves, though, you may have to pry up all the ends before you'll be able to remove any of them.
Continue in this way until you have removed all the boards from one wall to the other, then make another wall-to-wall cut a foot from the edge of the courses you removed, divide it into sections with perpendicular cuts, and continue prying.
Scrape off the adhesive from the subfloor with a floor scraper when you have removed all the flooring. If the adhesive doesn't come off easily, a floor buffer fitted with a scraping attachment will make the job easier.
Rent a floor buffer, if you don't own one, and ask for a floor scraping attachment. Hook the attachment to the bottom of the machine and run the buffer over the subfloor. It should remove most of the adhesive. Use a disk sander with a 100-grit sanding disk to sand off any that remains.