Chainsaw Repair

J, your description leaves a littany of items that could cause the symptoms. The problem could be something as simple as the saw being flooded, in the best case scenario, to a toasted piston/cylinder, as a worst-case scenario. Start by pulling the plug, grounding it against the cylinder, puller the starter rope and checking for spark. If you have spark and the plug looks wet, pull the starter rope 30x's with the plug removed. Then try to start it. If you do not get spark, pull the ground wire from the stop switch and check for spark again. Did you replace the plug after the problem started or before? You can try a different plug bc sometimes you see what appears to be good spark, but under the pressure of compression, the plug doesn't fire.
If the saw isn't flooded and you have checked for good spark. I would pull the muffler and have a look at the condition of the cylinder and piston. If the piston is smooth with no vertical scoring, then the problem is likely in the carb/fuel delivery system, or less likely in the coil/ignition system.
Check for flooding and piston condition, and report back. We will get it going for you.

I run regular 10% ethanol gasoline and Pennzoil Air Cooled oil at 32:1 ratio.

100:1 ratio with any oil including Amsoil will burn up your chainsaw.

Many people use Stihl Ultra synthetic oil at 40 or 50:1

The little silver 2.6 oz bottle of Stihl Ultra Synthetic mixed with 1 gallon of gas is 49:1 ratio which would work out fine for you.

I don't worry about ethanol. I run it mixed at 50:1 with Stihl Ultra.

I understand that ethanol eats up fuel lines etc, specially on older saws that weren't designed for it - and maybe some newer ones as well?   

Anyway, it isn't an issue to me, as I use only Alkylate fuel.