You need to overhaul the engine. Your first mission is troubleshooting: did the engine seize because the pistons seized, or because the main bearings seized? To do so, pull the heads and try to remove the cylinders. If they won't come off, piston seize. If they will and when you have them off the engine won't turn over...bearing seize.
Depending on the engine model, it can be very expensive. If it locked up, and won't turn over when you try to start it, then the engine is seized. You may consider buying a used engine from a salvage yard, or just sell the car.
An engine cylinder misfire is what happens when combustion is incomplete. How much it costs to fix will depend on the type of car and the year it was manufactured.
If you've pulled the plugs and the cylinders are full of gas, the motor is seized, won't turn at all (have you put a socket & bar on the crank?) then replace the motor with a used/rebuilt one would be the easiest.
depends on what is wrong with it you may need a new engine to fix it
That largely depends on the quality of the engine. If its a cheap/old one its junk. Most often a cheap engine is fatally damaged by a seize. However... The two main culprits are heat and lack of lubrication. So, allowing the engine to cool and making sure its properly lubed can sometime un-stick a mildly seized engine. (always check a small engine's oil level before each use) If it is jammed a bit harder spraying a penetrating lubricant (like PB Blaster) into the spark plug hole can help. Severely seized engines would need to be taken apart and rebuilt.
The exact cost to fix an engine cylinder misfire on a 2000 Mercury Mystique will depend on the exact type of engine it has, but can cost around $1,000.
Have vehicle scanned to determine the problem
Here is a video on how to fix engine code p0449
depends on what is wrong with the engine, if it is under warranty, what model and year car you have, etc. you cant just ask how much does it cost to fix an engine because all engines have different parts that cost different amounts.
Pretty much going to have to replace it. Because of the pressure involved, there is no easy fix.
Are you talking about seized brakes? As in the wheels no longer turn because the brakes are stuck? or.......?