Help! Brake Lockup

[amargari]

I took my car out for the first time in about 8 months because I was installing multiple items non brake related. Installed TPI and Vintage Air setup. I took it for a short ride and stopped at a friends house while it idled. I went back in the car to drive away and all four brakes were locked up. I tried to drive it and the engine eventually could not overcome the 4 brakes.

I tried to roll the car and all 4 brakes are locked. I unhooked the master from the booster and all brakes unlocked. I am running C5 brakes all around with a C5 Booster and Master. Is this a booster issue? The brakes worked well for about a year. The booster was used when I bought it.

BTW. Once the brake pedal was pushed down. It stayed in the down position and would not come back up. The pedal was extremely hard with no movement.