96Cutlass Supreme Brake Issue

Hello to all- need some help today with a brake issue on my 96 Cutlass Supreme. I started the car the other day & the brake pedal went down to the floor. This happened once before, a while ago, but after starting the car again it was okay. This time no luck. Where do I begin looking to find the problem? Can this happen if there is no brake fluid? Honestly, I have yet to check. Actually, the dash light for the emergency brake is also on. Seemed to come on periodically & now stays on since having replaced a rear hub bearing. That light came on once before also, after having a tire changed, then went out after removing & replacing the tire again. Cable not connected properly? Are the 2 related now? AF is always helpful. Any input is appreciated. Thanks!

That brake warning light is trying to tell you to check the brake fluid! Do that first and if the level is at the bottom of the reservoir, you have air in the system. The system will now need bleeding at all four wheels. In addition, you must have a leak somewhere, and you need to find that leak!