They HAVE to be INSTALLED on both machines....otherwise everyone would be hacking from a USB stick....
All the best Brett
TeamViewer uses a password and username system to connect, it isn't some auto instant connect boom! It requires login credentials to connect -_-
Also TV supports a portable version of their software that can be installed on a USB flash drive that runs on a platform from the USB drive. The portable console does not require any installment or elevated privileges of the computer to allow it to connect to another. (And that is what I am looking for, but in a free format!) Now the PC that you connect to with the portable software does require the program installed on it in order to make the connection.