OK, now I've put all my software back onto my 64 bit Win 8.1 PC, Dimension Pro 64 bit works as a standalone, Izotope Iris only works in 32 bit standalone, Ozone works as 64 bit Standalone, EZDrummer only works as a 32 bit....
 
The meters on the plug in seem to suggest sound should come out...  but nothing!
 
So confused!

Eggster
OK, now I've put all my software back onto my 64 bit Win 8.1 PC, Dimension Pro 64 bit works as a standalone, Izotope Iris only works in 32 bit standalone, Ozone works as 64 bit Standalone, EZDrummer only works as a 32 bit....
 
The meters on the plug in seem to suggest sound should come out...  but nothing!
 
So confused!

Sounds like you're saying you reinstalled the plugins, and now they won't work correctly...?
 
I would reinstall again, but do "Run as Administrator" (Right-click on setup, choose run as administrator).
 

I'll give it a try!

The original Ezdrummer requires installing the 32bit version then downloading and installing the 64bit plug-in. The 32bit Ezdrummer will not work in 64bit SONAR. IIRC, the original Iris standalone is 32bit only. Iris2 includes both 32bit and 64bit standalone synths. Both include 32bit and 64bit plug-ins in VST2 and VST3 format but the default VST2 path is not part of the SONAR VST scan path. I rarely use default VST2 plug-in paths preferring to use the default paths used by SONAR.