I use a padded laptop sleeve inside a padded backpack inside a pannier. Put the pannier inside the backpack once arrived at destination. Laptop has an SSD in it. Not a single hiccup in 4 years (nor a single virus), entering its 5 year of use.
I also use a metal case instead of a pannier sometimes that's even easier.
Last edited by erig007; 11-08-14 at 01:57 PM.