Question : How do I setup "completely" Unsolicited Remote Assistance Requests in Windows 7 for remote support? - Replacing free VNC

We have about 600 PCs/Laptops on a Windows Domain across approximately 20 locations.  We're purchasing more and more Windows 7 computers.

In the past we've used the VNC free version for unfettered remote access to our PCs/Laptops, especially the ones located in other cities via our MPLS WAN.  Users don't have to approve a request or even be there to login.

The VNC free version doesn't work with Windows 7.  We don't want to have to buy Real VNC, Radmin, or anything else x 600 computers if possible.

I've done some research but had difficulty getting unsolicited remote assistance to conveniently work.  One of the sticking points is that the user must approve the offer:  "When the assisted party approves the Remote Assistance offer..."

Must approve the offer:  we don't want the user to have to approve the offer.  We'd like to get in like VNC and allow users walking by to see that our support department is working on the computer.  If we don't want them to see what we're doing we'll simply use Remote Desktop instead.

Share Control of Desktop:  We don't want the user to have to approve this either.

Goals:
-Remotely enable Remote Assistance: I believe we can do this via Group Policy or remote editing of the registry (Easy, but there are firewall entries to check too)
-Remote control a computer while the user can watch the screen, without the user having to do anything (i.e. initiate or accept a request.)
-Ideally it would work even if the computer is at a login screen (no user is logged in)

This is the closest thing I've found and it's for Vista (which should still apply to Windows 7).  But a user still has to be involved to let you in and allow you to share the desktop.
http://technet.microsoft.com/en-us/library/cc505914.aspx

Answer : How do I setup "completely" Unsolicited Remote Assistance Requests in Windows 7 for remote support? - Replacing free VNC

Have you tried ultravnc? works with win vista/7.
http://www.uvnc.com/

I use it on win 7 and no issues