TRANSIT WITH NO BRAKES?

driving my 96 transit along the brakes were solid one minute then the next the pedal would travel all the way to the floor. Got it back home, thought the brakes might need bleeding, started at the back, slackened off the nipple 2nd person pressed the brake, tightened the nipple, foot off the brake, and repeated on all three wheels until the fluid came through. Cannot slacken off the drivers nipple and now no foot brake what so ever and cannot get even the smallest amount of pressure from the pedal. Have I done the bleeding correctly, if so is the fact I now have no brakes because I cannot bleed the drivers wheel or is it a case of the master cylinder? HELP PLEASE!!!!!!!!!!!its like the blind leading the blind