I understand that you reinstalled the operating system on your computer and lost the fingerprint reader on your computer and can't access the files locked using it.
Not to worry, I will be glad to help.
May I know the exact model number of your computer? Click here. Please do not share the serial number of your computer.
May I know the method you followed to reinstall the OS?
If recovery was done on your computer using the HP Recovery manager, all the applications bundled with the computer would have automatically been installed.
Please check your computer for the fingerprint software.
If it is not there, you can use the HP Recovery Manager application on your computer to install it manually. Click here.
If you have installed a retail version for OS, you can download the software from www.hp.com/drivers
However, I will not be able to help you unlock protected files.
Keep me posted.
Disclaimer: HP Doesn't recommend any upgrade/downgrade of any hardware parts or software that is bundled with the product. It may affect the manufacturer's warranty and performance. You can change the configuration at your own risk.