as long as you had them before the fork you can still use them, but with the new wallet. Save your wallet.dat file somewhere safe (you should always have offline backups anyway, eg on a USB stick that you keep in a safe location, fireproof lockbox, etc). Then install new wallet, run it and let it sync to the blockchain (might take a few days and a few lockups...there are links to a bootstrap on github to get you farther along). Then shut down the wallet, replace the wallet.dat created by the new wallet with the old one you had saved, and restart the wallet. Your coins should show up. Provided you still know the password (assuming you had the wallet encrypted) you can send these coins, stake them, or just hold on to them.