The simpliest probably would be to use the wallet you have used when creating this file.
Is your file a .dat file (e.g. wallet.dat) ? If so, this is a core wallet. You can download the client here:
https://bitcoin.org/en/bitcoin-core/.
Make sure to create several backups of your wallet file before trying to restore.
Install core and copy your wallet.dat file into the data directory of core. Afterwards you can dump the private keys (if you don't want to wait for core to be fully synced) and import them into a lightweight client [1].
If your wallet file is not a .dat file it most probably is an electrum wallet.
If this is the case you can simply (after backing it up!) install electrum [1] and open your walletfile with electrum.
You might need a password to access your coins (if you have set one when creating the wallet).
[1] Electrum:
https://electrum.org/#download