Then you should look for a hardware wallet.  It is a device that holds your keys, instead of your computer.  Passport is my most recommended one, because it is airgapped and operated by Seth For Privacy, a very respected and competent individual.  But, there are cheaper and more popular alternatives like Trezor.  If you are paranoid, then you should stick with airgapped solutions like Passport. 

(Think of airgapped as a device that never connects to the Internet)