are the laptops all windows based? if so,
here's one that looks promising. i appreciate the minimalistic approach and there's no installation required.
from the website:
Quote: "It's designed for portable use: only one file so you can run it from external USB drive. Doesn't write to registry."
i've not tested it nor can i vouch for it but it's open source (check the dev tab) and a place to start.
add: i went to download.com and looked it up.
3 reviews there that might help you decide (links to prior version, 0.9, for reviews).