First thing...stop overclocking for now till you get this issue fixed.
Secondly, here's a blurb from Abit about the Serial ATA drivers not initializing properly:
"Why could I not sometime recognize SATA hard driver by ICH5R SATA BIOS?
We suggest go into ?Advanced BIOS Features? for Delay IDE Initial (Secs)?of timing setting, and then increase the delay time, don?t forget to save the BIOS setting. We think that will fix it."
A bit of "Engrish" there, but you get the picture. Set the IDE delay higher by a second or two in the bios, save the settings, change boot device to HDD's (unless it's considered a SCSI), and try again.