Sorry for resurrecting this thread, but I registered just to have a say.
Currently upgrading our school OS to Win7 from XP and have come across this problem. Everything in the thread fits, from the admin accounts being able to see the volume icon while everyone else can't, to the fact I get a conflict message come up when adding the reg file, but still I have no joy. I have tried disabling 'replace the Windows Volume Control' but it makes no difference. Any help would be appreciated (and probably by ADoubleU above as well).
If there's anyone looking for the official RM Knowledge Base article for the fix (that doesn't always work) its here:
http://www.rm.com/support/technicalarticle.asp?cref=tec3549589
