What to do if you can't get an image from the remote PC (you can still connect via telnet or chat mode)?
You can create a registry key which will disable the option to change Radmin Server settings:
Forbids changing Radmin Server settings. The key type is binary with possible values of "01 00 00 00" (disallow) and "00 00 00 00" (allow). Of course, if the remote user has Administrator rights, he will be able to change the Radmin Server Settings despite of this registry key.
Why does Radmin 3 disable Aero Style in Windows Vista?
Radmin 3 uses its own mirror driver for desktop transfer. Windows Vista disables Aero Style each time any mirror driver starts. It is a feature of Windows, all mirror drivers would disable Aero Style. Microsoft Remote Assistance has the same behavior.
How to transfer sound from the remote PC?
You need to set sound input as a sound output and start Radmin voice chat. In our next major release Radmin will support sound transfer directly.
I clarify my answer for the community:
If you've already activated Radmin server, you can remove Radmin, reinstall it and activate again - that won't effect your license count. You cannot "overactivate|activate Radmin twice".
"...These are instructions for setting the MSI for NTI:
* Run Radmin MSI configurator
* Apply all changes, click OK (don't click next)
* Run Regedit -> HKEY_CURRENT_USER\Software\Radmin\Temp
* Modify \Server\Parameters TrayIconMode to 01 00 00 00
* Next -> Next etc.