Dell really likes ot make it tricky to get the fingerprint reader working when you install Windows from scratch.

Update 9/7/2012:
Good news! Dell has quietly released a single installer that takes care of installing all the sub-components correctly, in the correct order (thanks Mark for pointing this out). As of this update, the latest version (for the e6520) is here:

http://www.dell.com/support/drivers/us/en/04/DriverDetails/DriverFileFormats/Product/latitude-e6520?DriverId=TDC1K&FileId=2999613592&urlProductCode=False

The catch: you have to follow a specific procedure to uninstall any old versions. Also, I don’t know if this allows you to use the lighter-weight biometric framework version. I probably won’t try it until they start supporting Windows 8.

UPDATE 8/25/2011: Dell has released new firmware, software and several different drivers for the fingerprint readers, whihc I have not had time to evaluate yet. My experience with the first release of the “Data Protection | Access” is that is is poorly documented, incredibly slow, buggy, and flat-out not worth the effort. Fingerprint login took so much longer than password login that I stopped using it, and did not install the drivers when I later reinstalled windows.
When I get a chance to evaluate the new drivers (which will involve some image backups) I will update this post. See the comments for some more info.

…

Previously, you had to download several different ControlPoint packages and install them, hoping one was the right one. Well now as of the dell E6520 they have renamed everything to Dell Data Protection | Access (Dell data protection access). You will need to download these three packages and install in this order:

Data Protection | Access — Driver Package

Data Protection | Access — Middleware Package

Data Protection | Access — Application Package

You might also need the ControlVault driver, but I’m not sure – I did for safety’s sake. Update: Do NOT install the ControlVault driver. This will cause “no fingerprint reader found” rn 02000051 error message.

I hope this helps somebody.

UPDATE: If you did install the ControlVault driver, try using system restore to roll back (This is what I did after installing the driver a second time, after reinstalling windows to recover from the first time…). Uninstalling will not remove it. If System Restore doesn’t work, you will probably need to reinstall windows (or call Dell)
Reader Kristof posted some steps in a comment below that other folks confirmed successful – I’m quoting it here for reference:

I also installed the controlvault, but did not have to reinstall windows (restore points were disabled). I solved it as follows:
– uninstall controlvault
– remove fingerprint reader from installed hardware (when it asks, also remove driver)
– uninstall all other DELL Data Protection things you might have installed
– reboot
– reinstall ONLY the Data Protection tools as described in the post
– reboot

and then it just worked… (finally!)