Rebuilt brake system and brake now stuck

I rebuilt my front brake system today but now my front brake is gripping the rotor pretty hard. I can get the tire to spin with my front end off the ground but I cant get it to free spin.
I havent put fluid in it yet as I need to fill and bleed the system but luckily I noticed this before I started filling it up. What do you guys suggest? I rebuilt the caliper and seated the piston almost to the bottom. I take off the bleeder screw and all you can see is piston also. I also put new pads.

anyone? I cant get this thing rolling till I solve this problem.

Thanks anyways. I guess I'll follow up if anyone else has similar problems.
I took it out for a short ride and I went about two miles and barely used the brake and the rotor was way too hot after sitting for about ten to fifteen minutes. I invited my cousin to take a look as he has experience in sport bikes and it turns out the PO did a crappy band aid job on the caliper adjusting bolt. Hate asking family for help, anyways It wasnt as big of an issue before because the pads were worn thinner but it wasnt allowing the caliper to swing away from the inside bad enough to let it run free.