Yup, these guys are right..... pop a few covers and see if you can find the noise... by listening to these fellas, you should start with the clutch... easy stuff. There are lots of threads on here about how to remove the clutch (don't be jamming up the flywheel with screwdrivers or any such thing).
For cheap, you can have a nice backup saw (who am I to counsel you out of the new one?), which may come in very handy. You are then also well on your way to the "three saw plan" and so you should at this point start looking on Fleabay for a really big sumb*tch to round out the field. For what your dealer is offering you for it, I'd keep your old friend.
I've LOVED reading this thread, I've got a nice looking 028 that I bought as a non-runner for peanuts ($20). After farting around with it for a spell, it looks like a carb kit is going to put it back in service. After what I've heard, firewood season can't come quickly enough!