Teamviewer seems promising. Just have the client download and run (no need to opt "install") and random ID & password will be generated on client's screen for remote control. Run the same software on remote station to enter ID & password to control.
The other alternative being crossloop. Also free, but both sides must install software, which is a very easy procedure. After install, skip the create account page (by clicking "later" button to close it), tell the remote controlling party the access code.
All thanks to zoomjet.
I have tested both programs and they both work very well.
These are better than using the old fashion VNC or Logmein Standard.
Ammyy Admin is quite useful if you are looking for a remote control program very easy to use and do not give you any annoyance to the configuration of ports, firewalls and more.
Thanks for the input. There's a BUY page on the website, but I guess that is only for added features and the cost is reasonable.
Another very good alternative is using on premise RHUB remote support appliances. It is easy to use and works on both Windows and MAC computers.
It appears that this is NOT Free! Spam?