1> First uninstall the copy of Teamviewer from your system. This can be done with free uninstallers or by using Window’s default ‘Add or remove‘ program which can be found at: ‘Start’ –> ‘Settings’ –> ‘Control Panel’
2> Click on Start –> Run –> type %appdata% –> delete TeamViewer folder and also delete “C:\\Program Files\\Teamviewer”
3> Delete registry folder: hkcu/software/teamviewer and hklm/software/teamviewer
4> Refer to this tutorial to change the MAC Address: http://www.irongeek.com/i.php?page=security/changemac
5> Clean your systems registry – you can use a free registry cleaner for this purpose- http://www.techbuzz.in/how-can-i-clean-my-computer-registry-for-free.php
6> Once you have completely wiped out Teamviewer out of your system – install a fresh copy of Teamviewer. Ensure you select the option ‘Personal Use’ (I’m assuming that you are playing fair here) !