Old Bit Coin Wallet Failing to Pass 180 Weeks
First of all, backup your wallet.dat even if you are not going to do anything to the wallet.

I don't know if you are open to using other wallets, but you could recover your bitcoin by following these steps:


Unlock your wallet
Use the command dumpprivkey "YOURADDRESS" from the Bitcoin Core console 
Import the private keys on a lightweight wallet such as Electrum (Warning: There was a scam message being shown in Electrum sometime ago)