Found my wallet on my external HDD but it has changed the adress and it was empty after synchronising. I can see in blockchain.info that its not empty Can anyone help me,i found my wallet from 2013 on my HDD. I noticed that it has changed its adress and there were no BTC on it after synchronising on my laptop. I can see in blockchain.info.com that its not empty.
Bitcoin Core does not have "the address". There is no "the address" in a wallet. Wallets have more than one address, and every time you want to receive Bitcoin, it will give you a new address. This does not mean that old addresses are forgotten or deleted. They are still there and the wallet still knows about them.

You will not be able to see your balance without syncing the entire blockchain. If the version of Bitcoin Core you have is old, I highly suggest that you install the latest version of Bitcoin Core and let it sync from scratch. To do this, download and install Bitcoin Core 0.15.1 and then delete everything in the data directory except for the wallet.dat file. Then start Bitcoin Core and let it fully sync.