Stihl chainsaw ms441c put new coil on still no spark flywheel ok key way in place ground wires ok!

Check the ground wire on your coil and see if it is loose or well grounded...

According to Stihl's engine service manuals, when the engine has no spark or a dramatic, sudden loss in power, the problem could lie in the ignition system. The ignition system ignites the fuel in the engine for proper combustion. When the spark isn't firing correctly, an influx of gas can bog the engine down or cause it to not start at all. Since you are dealing with potentially lethal high voltage, extreme caution is advised and safety gear should be worn at all times.
first Slide the rubber spark plug connector off of the spark plug. On most Stihl's this can be accessed from the top of the engine, underneath the chain brake handle. Unscrew the air filter cover and remove it, if you can't see it on top of the engine
then Insert the socket wrench onto the spark plug and remove it from the engine. Discard the old spark plug and replace it with a new, identical spark plug, which will be recommended in your operator's manual. Make sure the spark plug is gapped according to your manual's specifications or else the engine won't start.
after that Turn the ignition switch to the "On" position. Insert the spark plug into the rubber connector. Make sure the chain brake is disengaged by pulling back on the black chain brake handle, which runs atop the saw's engine.
Hold the rubber plug and spark plug, with gloved hands, about 1 to 2 centimeters from a metal point on the engine block. Wipe any flammable gas or oil from the metal spot on the engine with the rag. Tug on the starter cord and look for a blue spark across the "hex" part of the spark plug,Check to be sure the wires leading to the "On-Off" switch aren't tangled or touching a metal point on the engine if there is no spark, Replace any wires if they are damaged or corroded

The ignition works off speed of rotation, so you need to crank the engine well withe the spark plug grounded, if there is still no spark, then the new coil is either incorrect for the model, or is faulty, also make sure the earth cut out wire on the unit is dissconected, to rule out a faulty switch or wire.

Be sure the magneto is gapped properly. A sheared flywheel key will cause timing issues but not eliminate spark. Either you have purchased faulty parts or spark is not your problem. Remove the ground wire from the coil, be sure you have tightened the flywheel nut properly, spray some carb cleaner in the carb and try to start. If it starts on the prime then you have spark and its a fuel problem. If it starts with the ground wire disconnected but not when the wire is connected then there is faulty wiring or a bad switch.

It is possible your flywheel has lost it's magnet strength, if you noticed it turn a blue. Can take off flywheel and replace with a good one. Or you can play with the gap on the magneto/coil, and insert a piece of paper between the coil and the flywheel magnets, to set for air gap.

Sounds like a tricky one. Have you checked the magetism/functioning of the flywheel.? Tracking back the problem by having a new spark plug and coil would next point you to the flywheel. Coil to flywheel gap should be 0.25 feeler guage.

Hope this proves useful. :)

The problem could be with the kill wire grounding out on the housing or the ignition coil could have gone out. Take out the spark plug and dis connect the kill wires off of the coil. NOTE: If you do not take out the spark plug to test for a spark then you run the risk of the unit starting up and not being able to shut it off. With the spark plug out of the engine and the kill wires dis connected. Put the spark plug boot on the spark plug and rest the spark plug on the engine (anywhere there is bare metal from the cylinder is O.K.) pull on the recoil starter and see if there is any spark present. If there is still NO spark present then you need to replace the coil. If there IS spark then you need to replace the kill wires with a new set.

check the ground wire on the on and off switch, it could be a bad ground

A business card placed between the flywheel and module works quite well (the magnetic attraction even holds it in place).and is easy. Rotate it by hand when done to ensure there is no contact. HTH
Lou