Computer crashed, total reinstallation. Have wallet.dat but not private key
As long as you have wallet.dat file and encryption key so you have nothing to worry about.

You can reinstall Bitcoin-core and move your wallet.dat file to bitcoin directory (./bitcoin on Linux) then you will be able to use it like nothing happened.

To get your private keys from wallet.dat you could run in your terminal

bitcoin-cli walletpassphrase "PasswordHere" 600
bitcoin-cli dumpwallet "txtfile_keysFile_path.txt"


All your private keys will be stored in that path.