2000 Jeep Cherokee Sport has brake pads that won't release after pressure removed from pedal... I think?!?

I just replaced the calipers, pads, and rotars in my 2000 jeep cherokee sport because I let my son drive the rig for a while and without me knowing he ground the rotar down to the thinnest I had previously ever seen and consequently melted the seal off the caliper from the heat! Needless to say I replaced both the penger side emly and the driver side embly but after completing the job (including bleeding the brakes ) upon going to move it out of the driveway to test the new stoppers I realzed the car wouldn't move?! So I ged it a little bit and the front two wheels were litereally being dragged by the back two across the ground without moving at all! It seemed as though the calipers were keeping the pads clamped to the rotars and not disengaging when pressure was removed from the pedal. Is this a master cylinder issue? Are the calipers I bought (which could be rebuilt) malfunctioning? What is your suggestion?