Yes, you can disable it in the BIOS.
1. Enter the BIOS.
2. Go to Integrated Peripherals section.
3. Go to Onboard PCI Device subsection.
4. To disable the SATA boot option disable the SATA RAID ROM option.
5. To disable the SATA controller altogether disable the Serial ATA Controller option as well.
Save your settings and exit. Voila, it's disabled.