What is the best tool to connect to a slow computer in a different city (Marondera)

Question

Sometimes i would like to see the screen of a computer used by a persons we work together on a number of projects. I want to connect to it, not without his knowledge. mostly because maybe I need to show him how to work on a certain web page in out project. Over telephone I'm saying one thing and they are seeing something else and we are so slow. What tools out there can help us share screens without eating too much of our internet and not blasting us with ads, malware or just being dysfunctional 'free' trials. free is better. we are on Windows machines 7+
my internet is very good (ADSL silver), theirs is an Ecoeb 2.5G dongle. not very good

Answer 1

Use Remote Assistance. Its possible for a friend or a technical support person to access your computer to help you with a computer problem or show you how to do something. You can help someone else the same way. In either case, both you and the other person see the same computer screen. If you decide to share control of your computer with your helper, you will both be able to control the mouse pointer.

Answer 2

My first choice is:

1.Teamviewer

2. Webex

They are both free and very economical on bandwidth consumed.