Try swapping power connectors, and or switching the direction of the cable. you made sure the red stripe lines up to pin 1, or blue stripe in the case of ultra ATA Cables. Also try a different IDE cable to be sure.
Make sure the CDrom's are on the secondary channel. Try swapping the CDRW to master and the CDrom to slave and see what happens. Change that cable too if you think it is suspect.
If the case is new, Try having the power supply swapped to see if perhaps it is somehow defective in some sort.
One last thing, Clear the Cmos and when it is finally loaded, set the clock, then load bios defaults or setup default settings. Try booting.
Make sure primary video device is set to the type of video card as well.
Feel free to e-mail me,
ashman@peachparts.com if you need any help and I will do my best to help you.
Alon