After following everybodies (kind) advice, I have removed omnisphere, trilogy and RMX from my new win7 64 Cubase 5 64 bit system. I also removed all libraries.
I have completely reinstalled omnisphere from the orginal disks - it worked, but when I then updated to 64 bit - and correctly identified the path to the sample libraries, I find that Omnisphere cannot find the default multi or the samples.
I have rung the US support line but its an answer phone. I am UK.
I have put a shortcut to the STEAM folder in with the omnisphere dll. Both the library and the dll are in bespoke locations. There are no other spectrasonic libraries or omni dlls on my system apart from the 64 bit one. I have deleted the 32 bit one as my whole system is 64 bit.
Can anyone help please - three days of installation grief so far.
thanks for the help