Contrary to what has been suggested in the comments, this is actually possible, just pretty difficult to arrange, and requires you to be willing to disable driver signing to install a Microsoft driver.
First go to https://www.microsoft.com/en-gb/download/details.aspx?id=38826 to manually download a copy of the Surface Pro 3 drivers. The driver package you want is currently called SurfacePro3_Win10_160128_0.zip
but the important things are that you want the ZIP archive of the Windows 10 drivers.
Inside that ZIP file there is a directory \Drivers\Accessories\SurfaceFingerprintSensor
. Extract the contents of this directory somewhere - your desktop will be fine.
You won't be able to install this driver because it's signed for Windows 10 not Windows 8. However, you can cheat. Use the Settings button on the Windows 8 menu to go into the Metro settings. Select Change PC Settings
then Update and recovery
then Recovery
. At the bottom you will see an option labelled Advanced Startup
. Press that button to reboot into the Advanced Startup menu. (There are a number of other ways to get here - see, for example, http://pcsupport.about.com/od/windows-8/a/open-advanced-startup-options-windows-8.htm for a list.)
In Advanced Startup, select Troubleshoot
then Advanced Options
. Then Startup Settings
. Your PC may reboot, and if you are using Bitlocker, you may need your Bitlocker recovery key to access this menu.
Select option 7
to disable driver signing enforcement. This is not to be recommended under normal circumstances, but all we'll be doing is installing the one Microsoft driver and then rebooting.
Once the PC has booted, go into the directory where you copied the files, and right click on the SurfaceFingerprintSensor.ini
file, and select `install. Your driver will now install. Reboot the machine, and your fingerprint sensor should now be working. Use Device Manager to check that it has installed correctly.
Once this is done, from Windows 8 settings, go to Change PC Settings
then Accounts
then Sign in options
. There should now be an option available to register your fingerprints.
This may possibly work for Windows 7 as well.