Im using the phantom 530 case and the front light has a brighter light inside of it and because I have my pc in my room its hard for me to sleep with it on! it flashes on and off.
If it's flashing it's probably the hard drive activity light. If you want to stop it you can just unplug it from your motherboard.
HDD led.
check your manual.
If you dont want it, then simply unplug the HDD led cable from the front panel header on the mobo.