1993 350 Trail Boss - Locked up?

Have a 1993 350 Trail boss that was just purchased.(actually by friend of mine)
Appeared to be in great condition. Ran great.
Got it home, rode it around, no problems.
Went back out to start it - electric start wouldn't turn it over.
Tried the pull start, and it acts as if the motor is locked or siezed up.
All fluid levels look normal.
It will not turn over, like it's vapor locked or siezed up.

Any ideas?  maybe the ones that say that it's a simple fix and not a major motor problem  

Thanks in advance,
Maver!ck