Anti Virus + Malwarebytes + Spybot search and destroy.
Encrypted Thumbdrive with all passwords stored offline
Ledger Nano S for Bitcoin and some others
Wallet.dat files saved and backed up on encrypted drive.
Most wallets with coins kept in offline PC, except staking wallets but I ensure I back up those every 3 days with and have a very strong password and only unlocked for staking.
As others have said never click on .exe files that you do not know the source of and don't trust any link sent from an email even if sent from a friend or family.
This is really good advice.
I personally use Comodo (NSA recommended) + Malwarebytes + Spybot
I would suggest you have a cold storage and hot storage. A cold storage is essentially an offline wallet (Ledger Nano or Trezor) and hot storage are wallets you use for liquidity (only the amount you are willing to lose). If you are storing your wallets on a machine you watch porn/torrent with..scan as often as possible.