Do you have your overclocked settings saved using one of the saved profiles in the bios?
If yes, you should be able to load the saved overclock profile and write down the settings.
After you've copied the settings you will probably need load optimized bios defaults.

Note: Check that your motherboard battery is not dead, it should register 3.0 volts or slightly higher.

If you follow the following instructions to clear your CMOS you might be able boot again with overclocked settings:
Clearing the CMOS --> http://forums.tweaktown.com/gigabyte...tml#post258596, post #2

Check out Q9400 Overclock EP45T DS3R Help, post #143 for some settings that might help with some ballpark settings.

For additional overclocking information, you can also use the forum's Advanced Search feature to search for threads with EP45T in the title.

The Advanced Search feature is near the upper right corner of forum web pages.