Actually, even though we DO need to remote control an office pc from a cruise ship, the more generic way to ask this is: how to remote control without having to download an activex or Java or anything else.
Here are some details of our configuration:
In the office we have Microsoft Windows Server 2008 (not SBS), and 5 workstations, a mixture of XP and Windows 7. We have a SonicWall device that we use to connet remotely under "normal" circumstances... that is, where we can download an activex control or configure our browser to user jave. However, from time to time, we need to access one of our PCs from a hotel lobby computer, or in this case, from a cruise ship computer, where we will have no ability to download anything onto the remote computer.
We do ahve the liberty to configure our firewall in the office to open up a port or something... our need really is to find some (free?) software that doesn't require ANY installation on the remote computer.