Is the Seagate SATA2 also? Are they AHCI/NCQ enabled drives?
If yes then press DEL to enter setup on startup, and go to the menu 'Integrated Peripherals' and set SATA/IDE Ctrl Mode to AHCI/IDE. If your drives are not both capable of AHCI/NCQ then set this to IDE. Set SATA Port 0-3 Native Mode to enabled.
If you're running some weird RAID config and forgoing the lost drive space then of course set it to RAID.
No press ESC to jump back to the main menu.
Now go to menu 'Standard CMOS Features' and go into each IDE Channel to auto detect your hard drives. Hopefully you put them on different channels (i.e IDE 0 and IDE 1), so set the option in the drives channel menu to 'Set Channel 0 Master' to manual. This is the bit I was trying to explain above, this sorted my double beeping and speeded up boot time auto detection.
Any problems write back here