Windows probably wont find the latest drivers by itself as they wont have been certified yet.
As Simon says, uninstall from the device manager and then do Scan for Hardware Changes or reboot but when it tries to load the old windows drivers cancel it. Then open the device manager again and double click on the scanner which should now have a yellow ! or ? next to it. Go to the reinstall driver part and select the let me choose the location or words to that effect and go to the folder where you saved the latest drivers to.
It will probably say that these drivers arent certified by MS but press continue anyway and they should install