Terri,
First - Dr. Felix is ok. They had me do that, too. I downloaded it but before I ran it, I had Avira check it out and it was clean. It's a bit of a pain that it puts the zip it created on the Desktop so the first thing I did (before I even looked at it or passed it on) was move it! It contains several files and is basically just what is running on your machine and what levels of different software. It's totally benign.
It does NOT control your computer. It just reports on what you have and what levels.
As far as Window's Update, I'm not sure how it knows that RealTek or NVIDIA have updates. It may be the way that HP set things up. I just know it does. The first update I did for NVIDIA was right after I got my machine. I had to uninstall the existing driver and then install the new version. HP's Tech Support walked me through that. Since then, I haven't had to do the uninstall bit manually.
Your Update may already be doing it. Check the history of updates and see if there are any for your graphics driver. I never let the update program even download, much less install the update, without first telling me and asking my permissions.
Diane