How can I delete my Wallet (deleting the Wallet file) AND disable the blockchain address to prevent accidential money to be send and lurking there forever without access for anyone?
There's no way to "disable" an address; all addresses, including those that have never had code deployed or transactions originating from them, are valid addresses to send ether to. A contract can reject a transfer by sending the ether back, but there's no way to deploy a contract at a specific address.
Deleting your wallet file doesn't really "delete" your address off the blockchain.
If you are worried about accidental eth being sent to the address you're talking about, it would be better to keep the wallet file and send back any eth that was sent to you.