unable to open teamviewer

two seperate issues

either teamviewer will not open , on dbl clicking icon asks for administrator privelage to make changes to the computer then on clicking ok nothing happens.

or if opens teamviewer allows connection for 20 seconds and then stops and breaks connection.

have repeatedly uninstalled restarted computer and reinstalled. Also edited registry as  a previous solution suggests not effect.

Present status is it will not open at all, on opening task manager it starts then fails. please advise