Big Problem

ur gonna have to take every thing apart and clean it real good, take the head off and see if the crank turns, the piston could be just rusted in the cylinder, also take off the clutch cover and clean real good, if it still dont turn, u will have to split the cases and check for seized crank bearings
 
if i have to split the crank case will the transmission gears fall out. also where is the cheapest place online to buy parts. i know i will need new bearing and gaskets and rings at the least. sorry to sound like a noob. i have rebuilt car motors but no 2 strokes lol.