Best software to connect to remote users?

Hi all,

I want to know which is the best software that I can use in my organization to remotely connect to users. Software should also support;

  1. I should be able to remotely deploy the client version on the workstation.
  2. Regardless of OS(Win XP/7/8) in the workstation, I should be able to log off and login to another account via the remote software. (When using netsupport, I was able to switch between users in Win XP but in Win 7 & 8 when I logged off from 1 user, the screen goes blank and I cannot see anything. User at the remote location had to come and press “Ctrl+Alt+Del”, in order for me to continue.)

Thank you…