Try spraying the bolt with a spray called "liquid wrench" I've used it several times and it works. You may have to spray it several times and let it soak in before the bolt will turn. And...have you tried using a breaker bar, or a cheater bar? There is a risk of breaking the bolt, but it also may just loosen the stubborn bolt.
If the cranks shaft pulley is seized, the whole engine is seized.
It's spring loaded, use a wrench or socket to move it. If it's really stuck it may be seized.
Seized should mean that it's not turning. Crank the engine and see if the alternator pulley spins or not.
Bearing seized on the pump.
When an engine is seized up, it will not turn over. The crank cannot make a rotation. Take hold of the main pulley and try to turn it. When you cannot turn the engine over, it is seized.
Air pump seized internally
the only way to fix is to have a garage repair (most likely replace) the AC compressor. You can buy a new belt that is shorter and skips that pulley. I have taken mine to Autozone and we tried 4 or 5 different belts until we found one that fits.
Possibly a worn belt, seized/partially seized pulley (contacting serp. belt), worn belt tensioner or something melting to exhaust manifold.
The Air conditioning compressor is likely seized. There is a clutch in the pulley that engages the compressor when the A/C is turned on. You can easily check the compressor (with engine off make sure the pulley has had time to cool off as it will be very hot) Try to turn the most center part of the pulley. If you cannot turn it by hand the compressor is seized. The smoke was MOST likely from the serpentine belt rubbing on the seized pulley when the A/C compressor was engaged. Please note that the same belt drives the power steering pump. This belt will be destroyed from the heat and must be replaced to prevent a possible steering failure.
If the fanbelt is also routed around a tensioner pulley, then the pulley may be seized. Or you may be adjusting it too tightly.
A bad pulley (sharp edge) A seized pulley A misaligned pulley
Something has seized. Check all the pulley's the belt runs around are turning freely (remove the belt to do this).