If the addresses you found have no transaction history you are looking at the wrong wallet.dat file. If you have the original hard drive then there is a possibility you may be able to recover the previously erased wallet.dat file and extract the private keys from that. I know datarecovery.com in Toronto has repaired lost/corrupted wallet.dat files in the past, they charged one guy 800$ and recovered 30k$~ for him(this was a few years ago, source: ( https://www.reddit.com/r/IAmA/comments/2n02lt/iama_data_recovery_engineer_i_get_files_from ) You may need to pay upfront if you can't prove or provide an old address with a proven balance.   If you're certain there were Bitcoins on that laptop DO NOT throw it away or give up.