I have the EXACT same motherboard as you (by the way, your motherboard isn't stable at 1800MHz FSB either, right? Hope I'm not the only one), and to overcome this I did the following:
-Unplug Computer
-Remove CMOS Battery
-Put jumper into non-overclocking position
-Plug in computer
-Put in CMOS Battery
-Boot into BIOS, overclocking should be disabled
-Shut down
-Move jumper back into overclocking mode
-Done
.
G'luck! This has happened to me too before.
-Unplug Computer
-Remove CMOS Battery
-Put jumper into non-overclocking position
-Plug in computer
-Put in CMOS Battery
-Boot into BIOS, overclocking should be disabled
-Shut down
-Move jumper back into overclocking mode
-Done

G'luck! This has happened to me too before.