Hello cassiereroni,
I see that you are having problems with the fingerprint reader on your computer. I have some information that may be helpful to you.
Here is a link to some troubleshooting steps for fingerprint reader issues that may be helpful if you start having trouble with the fingerprint reader in the future.
As for setting your daughter up with using the fingerprint reader there are a couple of options that you can use. Here is a link to a document on using the fingerprint reader in Windows 8.
If she has her own user account on the computer there is a section that talks about using the fingerprint reader on multiple user accounts. If you both share an account then you may have to add a fingerprint and have her use her finger. Select the section for adding and deleting fingerprints to add her fingerprint.