...if it never has the internet connection, if wireless connections are disabled, and if it is with you at all times, like a light laptop. Besides, all memory sticks you use with that computer should never touch another computer and they too should be with you at all times.
Too paranoid? But I have done this myself in the past, because some antis and such knew me before I even had my first internet connection a long time ago. I have always had many computers, and one of them was a laptop that was with me at all times. Ask NFiH -- though that nick is not around any longer.
But of course you should try to secure your internet computer reasonably well, as well as possible, so you got a point there, j_k.