brake locked up y and how to fix it?

It is not safe to drive, it will catch fire if the brake is not released.

It sounds like your caliper needs to be replaced on that wheel.

It is fairly simple to replace but a little tricky to bleed the air out of the system afterwards. Not a good thing to learn as you go with brakes, better have someone experienced help you or let a shop do this one.

Good Luck!

disc brakes dont have return spings in them, they purely work by the force of the rotor spinning pushes the pads just far enough away to allow rolling the wheel. the brake fluid presure is released as soon as you release the pedal. the only points I can see where something could have happened would be the master cylinder froze (not likely) abs valve stuck in some closed position (possible) or you ran it till the pads were totally gone and you fused the metal backings to the rotors in all cases no driving!!! if you should open the pet cock on the back and find the fluid sprays out (not dribbles) after it has set for a while this would verify a blockage.

yes somewhat easy to replace cabiler which is likey your problem here is a few ways most are about the same.. if you look might fine a video of how its done done one you can do any brake are not hard to do once you know how.. no not drive !!! it can catch a fire sorry!!! ... you can fix it at home easy just do some reading on how its done