DualDesk

DualDesk is powerful, easy to use ad-hoc remote support software that is a
one-time purchase and lets your technical support staff remote assist a
PC anywhere on the internet through firewalls in less than 5 seconds with
no configuration. Work smarter, save time and money providing full remote support help desk services to multiple clients simultaneously. Transfer files, chat, re-boot & auto-reconnect and control a remote system in real-time without pre-installing software on the remote computer even in "Safe Mode".