I upgraded my DAW from Windows XP to Windows 7 64 bit and had problems reinstalling Halion Sonic for ‘all users’. I thought I’d share it here in case anyone else is affected.
I have two users on my Windows 7, both me. One is the real Administrator and the other is my every day user account. The real Administrator is in fact the ‘uber secret Administrator’ that Windows 7 installs unknown to you! When I first installed Windows 7 I gave myself a user account with Administrator rights but got increasingly annoyed that the system was blocking me every now and then as I was re-installing and configuring my 40 or so applications. I discovered from a Windows 7 forum that this was the invisible Administrator at work! They have a hack for forcing it to be visible, which I carried out and life became easier - I was in control of my own PC again instead of HAL! 
Anyway, back to the issue. I opted to install HS for all users but afterwards only the user where I’d done the install had full access. The other user had no standalone version icon on the desktop and when the synth was loaded in Sonar it appeared but with no content at all. Looking for a fix before contacting Steinberg Support, I opened the first user’s folders under C:/Users/[User Name]/AppData/Roaming/Steinberg and copied the four folders Content, HALion Sonic, HALion Sonic_Standalone_64, and HALion Sonic_64 across to the equivalent place in the other user’s folders. This made averything work except for the missing desktop icon to launch HS standalone for the second user. To enable this I dragged a shortcut from that user’s Program Files/Steinberg/HALion Sonic/HALion Sonic.exe file to the desktop. This works but you only get a standard Steinberg icon for it rather than the ‘HS sphere’ one the first user has.
I’d be interested to know if anyone else encountered this problem, i.e. whether it’s a universal glitch or not.