OK,
So I downloaded a wallet. It synchronized to the network. it says I have nothing. Is this possible?
mind you I have a file on my computer that contains blockchain data that's rather large.
Can I do anything with that?
blockchain data is rather large indeed - let say few GB xD it is downloading with your wallet (Perhaps you are using Core) and it is needed for wallet to be synchronized with Bitcoin network.
You have any file with your private-keys that you want to import? (those are pretty tiny anyway
)
Answer : yes it is possible that you have nothing. If you never bought or earn any BTC it is highly possible (let say 99.99999999% chance that you have nothing)
If you had some coins, and now you have none - there are few possibilities:
-You spent them
-You lost them