If you installed SATA drivers when you installed your drive, it actually is probably running as SATA. The reason that BIOS didn't pick it up, might be because of the extra "abstraction layer" of software, applied by the driver.
Older boards do not respond to running mixed mode drives as well as newer ones.
Since you do not have RAID (per se), you did not need the RAID controller panel.
However, I'm thinking that the driver itself is still installed, and you should give a lot of serious thought before you try to further tamper with it, or remove it all together.
There is a "RAID mode called "JBOD" (Google that), which is probably how your system is running.
If you tamper with the driver, you may wind up having to do a complete reinstall of the OS.
For academic purposes, newer boards make it much easier to emulate the IDE mode with SATA drives, in some cases selecting that mode, when only one drive is installed at first boot.