Hey there again! – no, unfortunately not (that’s if you’re talking about PCs), as we need the flexibility to get our computers to do what we want. This flexibility comes with a price, to corrupt binaries.
I suppose if we went for the Harvard Architecture, or a derivative of, to separate programs from data, that might be nearly possible, but again getting new programs in will be slightly more of a hassle than the present computers.
I guess if everyone were careful about what they download – as careful as they are with their own wallets – we could frustrate virus writers enough for them to go away.