check the bios settings...if in the new case you have the case fans connected to the ps and not the mb you can turn them off. it the cpu temp fan warning you dont want to turn off and you want to check that you put the cpu fan on the right header.
Check your CPU fan - ensure the cable is not tangled in it (common occurance). Make sure the CPU fan is plugged into the CPU_FAN header (the chassis fan should not be plugged into that) and the fan spins when the computer is powered on.
I thought of this also, was the fan mounted to the door panel or the rear with a shroud?
If so, you don't currently have a CPU fan and you will need one for proper cooling or run the very real risk of burning up your CPU. If this is the situation, you can get anything from a stock HSF for the CPU up to a full water loop for cooling but you will have to put on a new heatsink before you can use the computer.