http://www.ext2fsd.com/ has everything for a Windows user. Works fine on my Windows 7 laptop.
1. Use the installer to have the driver. Alternatively get .zip archive and do a manual installation (install xp or install w64). Run as Administrator on Vista/7 !
2. Start ext2fs Manager, this will load the driver. It may happen you need to open Options and uncheck "mount as read-only".
3. connect DR 800 to Windows, you'll see SD card as say disk Y:
4. *backup *all* SD content*
5. start cmd.exe, browse to installed ext2fs files (Program Files/??? or your manual installation folder in case of using .zip archive)
6. to format Y: as ext2 do............... Mke2fs -b 4096 -L DR800 Y:
7. once done you can copy the books to SD as it is accessible with ext2fs driver.