Have you considered running Windows 8 Preview on that slate? It is designed for slates with a touch button Start screen. You can get support for it and the download at http://www.eightforums.com/
That sounds like your SSD not the SATA controller.
The SATA controller will be in the chipset from the HP Downloads webpage for your model: HP Slate 500 Tablet PC*-* Download drivers and software - HP Business Support Center
If you unzip the chipset to the location of your choice by running the .exe, it says in the Read Me that the storage (or HD) drivers included are for:
- IDE/ATA33/ATA66/ATA100 Storage Support
- SATA Storage Support
You want to run the .exe to unzip the drivers to a stick or CD, changing the root directory when it shows where it will unzip them. It will take some detective work to determine which .inf files are for those drivers, but the Load Drivers explorer should only take storage controllers so eventually you should get them installed if you browse far enough, likely into the Vista folder..
If you need more specific help ask in our Drivers forum where there is more expert help in tracing and loading these drivers.