I have a BTC address written down. The original client was lost in a HD crash, no coin in it. Can I use the same address, by creating it in a new wallet? No transactions were ever made with it.
The address will still be able to receive bitcoins, but if you don't have a backup of the private keys, you will never be able to spend them, exchange them for cash, or send them anywhere. They will be permanently stuck there.
If you have a backup of the private keys, then you can certainly be able to import the address and private key into a new wallet and continue to use it.