I found the following information on the Abit FAQ site for your board.
My system cannot power on successfully without recycling the power core. Why? (KT7/KT7-RAID)
If you meet the following booting up problems, clear cmos data may help.
Cannot power on the system. Recycling the power core can power on
successfully once. But you still have to recycle the power core
again the next time.
Do some bios setting, after save and exit setup screen the system
doesn't reboot. You need to recycle the power core to boot up.
There happens to be some garbage data left in cmos. Maybe owing to
update bios version, overclocking or whatever.
Power off the system
Clear cmos data by jumper. Move the jumper from default 1-2 to 2-3 for several seconds then back to 1-2 again.
Power on the system and hit <Del> to enter bios setup screen.
Set correct CPU speed in softmenu3 and do other settings. Save and
exit bios setup screen.
Does the correct memory count and processor/speed show on boot?
You may also need to update the bios/flash, but if you choose to do this, be careul to read the proceedure on the bios page regarding RAID.
By the way, are the motherboard jumpers/DIPP switches set correctly, if any, on the motherboard?
The faq page is here;