Ok. First thing first is it a two stroke or the later four stroke. I am guessing its a 2 stroke.
If it is a two stroke it could of siezed in several places
1 the piston and rings which has proabably damaged your bore and so will need a rebore. You will need a new piston set and a rebore. Top end strip down as long as you know what your doing then its not a terrible
2. bearing on the crank. If this is the case then its a much bigger job, split the engine and a strip down. Bit of a job.
bb
February 2010