CrossLoop is a completely free remote support tool. Its main function is giving access to a colleague or a friend to your computer in order to offer help for certain issues.
Or vice versa, one can provide remote support for whoever asks for. A simple installation is followed be the assignment of a 12-digit code.
This code changes every time one opens the program. Full access to the PC is granted as soon as the person at the other end types in the code and hits connect. Unfortunately, multiple-user connectivity is not yet available.
However, file transfers and secure encryption cover the basics of decent remote support software.