I don't have any particular experience with appraising violins myself, I only know about how the process works! Try finding a qualified, trusted appraiser online. (Or, more than one if possible to get multiple opinions.)
I don't know what I was thinking when I answered this question a year ago, and now I can't comment on my own response or edit it. Everything else I said was true, but Stradivari was still alive in 1727. Must have misread the year the first time.
If you violin has no strings, it's not in "good" condition. It may look good, but it is going to require serious adjustments before it will sound good. Also, if the year is right, it's not a Stradivarius. It's too young. It probably isn't a Stradivarius anyway, since all violins made by Stradivari are carefully tracked, so their whereabouts are always known. It might be an early Stradivarius copy, which brings us back to the condition of the instrument. If you can't get a good sound out of it, the violin is not worth it's weight in firewood, no matter how old it is. Take it to a violin shop and see if it can be repaired. Then, ask the violin shop for an appraisal. If they can't do it, they will likely know who can.